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BIDSError Reference

psychopy-bids validates event fields early and raises explicit error classes when values are invalid.

Practical Debugging Pattern

Use explicit exception handling around event creation in Coder workflows:

from psychopy_bids import bids

try:
    event = bids.BIDSTaskEvent(onset=0.0, duration=0.5, trial_type="stimulus")
except bids.BIDSError as exc:
    print(f"BIDS validation failed: {exc}")
    raise

Typical Causes

  • OnsetError: onset is missing or not numeric.
  • DurationError: duration is negative or otherwise invalid.
  • TrialTypeError: trial_type does not meet expected constraints.
  • SampleError: sample value is invalid for the requested event.
  • ResponseTimeError: response time is negative or malformed.
  • HedError: invalid HED payload format.
  • StimFileError: malformed stimulus path metadata.
  • IdentifierError: invalid identifier field.
  • DatabaseError: invalid database field.

API Details

BIDSError

Bases: Exception

Base class for all BIDS-related exceptions.

This class serves as the base exception class for all exceptions related to BIDS (Brain Imaging Data Structure) specifications and operations.

Source code in psychopy_bids/bids/bidserror.py 
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class BIDSError(Exception):
    """
    Base class for all BIDS-related exceptions.

    This class serves as the base exception class for all exceptions related to BIDS (Brain
    Imaging Data Structure) specifications and operations.
    """

OnsetError

Bases: BIDSError

Exception raised when onset value is incorrect.

This exception is raised when the provided onset value does not meet the expected criteria for correctness according to BIDS (Brain Imaging Data Structure) specifications.

Source code in psychopy_bids/bids/bidserror.py 
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class OnsetError(BIDSError):
    """Exception raised when onset value is incorrect.

    This exception is raised when the provided onset value does not meet the expected criteria
    for correctness according to BIDS (Brain Imaging Data Structure) specifications.
    """

    def __init__(
        self, onset: object, msg: str = "Property 'onset' MUST be a number"
    ) -> None:
        """Initialize the OnsetError instance.

        Parameters
        ----------
        onset : object
            The onset value that caused the error.
        msg : str, optional
            Explanation of the error.
        """
        self.onset = onset
        self.msg = msg
        super().__init__(self.msg)

    def __str__(self) -> str:
        """Return a string representation of the error.

        Returns
        -------
        str
            A string containing the onset value and the error message.
        """
        return f"{self.onset} -> {self.msg}"

__init__(onset, msg="Property 'onset' MUST be a number")

Initialize the OnsetError instance.

Parameters:

Name Type Description Default
onset object

The onset value that caused the error.

 required
msg str

Explanation of the error.

 "Property 'onset' MUST be a number"
Source code in psychopy_bids/bids/bidserror.py 
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def __init__(
    self, onset: object, msg: str = "Property 'onset' MUST be a number"
) -> None:
    """Initialize the OnsetError instance.

    Parameters
    ----------
    onset : object
        The onset value that caused the error.
    msg : str, optional
        Explanation of the error.
    """
    self.onset = onset
    self.msg = msg
    super().__init__(self.msg)

__str__()

Return a string representation of the error.

Returns:

Type Description
str

A string containing the onset value and the error message.
Source code in psychopy_bids/bids/bidserror.py 
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def __str__(self) -> str:
    """Return a string representation of the error.

    Returns
    -------
    str
        A string containing the onset value and the error message.
    """
    return f"{self.onset} -> {self.msg}"

DurationError

Bases: BIDSError

Exception raised when duration value is incorrect.

This exception is raised when the provided duration value does not meet the expected criteria for correctness according to BIDS (Brain Imaging Data Structure) specifications.

Source code in psychopy_bids/bids/bidserror.py 
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class DurationError(BIDSError):
    """Exception raised when duration value is incorrect.

    This exception is raised when the provided duration value does not meet the expected criteria
    for correctness according to BIDS (Brain Imaging Data Structure) specifications.
    """

    def __init__(
        self,
        duration: object,
        msg: str = "Property 'duration' MUST be either zero or positive (or n/a if unavailable)",
    ) -> None:
        """Initialize the DurationError instance.

        Parameters
        ----------
        duration : object
            The duration value that caused the error.
        msg : str, optional
            Explanation of the error.
        """
        self.duration = duration
        self.msg = msg
        super().__init__(self.msg)

    def __str__(self) -> str:
        """Return a string representation of the error.

        Returns
        -------
        str
            A string containing the duration value and the error message.
        """
        return f"{self.duration} -> {self.msg}"

__init__(duration, msg="Property 'duration' MUST be either zero or positive (or n/a if unavailable)")

Initialize the DurationError instance.

Parameters:

Name Type Description Default
duration object

The duration value that caused the error.

 required
msg str

Explanation of the error.

 "Property 'duration' MUST be either zero or positive (or n/a if unavailable)"
Source code in psychopy_bids/bids/bidserror.py 
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def __init__(
    self,
    duration: object,
    msg: str = "Property 'duration' MUST be either zero or positive (or n/a if unavailable)",
) -> None:
    """Initialize the DurationError instance.

    Parameters
    ----------
    duration : object
        The duration value that caused the error.
    msg : str, optional
        Explanation of the error.
    """
    self.duration = duration
    self.msg = msg
    super().__init__(self.msg)

__str__()

Return a string representation of the error.

Returns:

Type Description
str

A string containing the duration value and the error message.
Source code in psychopy_bids/bids/bidserror.py 
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def __str__(self) -> str:
    """Return a string representation of the error.

    Returns
    -------
    str
        A string containing the duration value and the error message.
    """
    return f"{self.duration} -> {self.msg}"

TrialTypeError

Bases: BIDSError

Exception raised when trial_type value is incorrect.

This exception is raised when the provided trial_type value does not meet the expected criteria for correctness according to BIDS (Brain Imaging Data Structure) specifications.

Source code in psychopy_bids/bids/bidserror.py 
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class TrialTypeError(BIDSError):
    """Exception raised when trial_type value is incorrect.

    This exception is raised when the provided trial_type value does not meet the expected criteria
    for correctness according to BIDS (Brain Imaging Data Structure) specifications.
    """

    def __init__(
        self, trial_type: object, msg: str = "Property 'trial_type' MUST be a string"
    ) -> None:
        """Initialize the TrialTypeError instance.

        Parameters
        ----------
        trial_type : object
            The trial_type value that caused the error.
        msg : str, optional
            Explanation of the error.
        """
        self.trial_type = trial_type
        self.msg = msg
        super().__init__(self.msg)

    def __str__(self) -> str:
        """Return a string representation of the error.

        Returns
        -------
        str
            A string containing the trial_type value and the error message.
        """
        return f"{self.trial_type} -> {self.msg}"

__init__(trial_type, msg="Property 'trial_type' MUST be a string")

Initialize the TrialTypeError instance.

Parameters:

Name Type Description Default
trial_type object

The trial_type value that caused the error.

 required
msg str

Explanation of the error.

 "Property 'trial_type' MUST be a string"
Source code in psychopy_bids/bids/bidserror.py 
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def __init__(
    self, trial_type: object, msg: str = "Property 'trial_type' MUST be a string"
) -> None:
    """Initialize the TrialTypeError instance.

    Parameters
    ----------
    trial_type : object
        The trial_type value that caused the error.
    msg : str, optional
        Explanation of the error.
    """
    self.trial_type = trial_type
    self.msg = msg
    super().__init__(self.msg)

__str__()

Return a string representation of the error.

Returns:

Type Description
str

A string containing the trial_type value and the error message.
Source code in psychopy_bids/bids/bidserror.py 
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def __str__(self) -> str:
    """Return a string representation of the error.

    Returns
    -------
    str
        A string containing the trial_type value and the error message.
    """
    return f"{self.trial_type} -> {self.msg}"

SampleError

Bases: BIDSError

Exception raised when sample value is incorrect.

This exception is raised when the provided sample value does not meet the expected criteria for correctness according to BIDS (Brain Imaging Data Structure) specifications.

Source code in psychopy_bids/bids/bidserror.py 
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class SampleError(BIDSError):
    """Exception raised when sample value is incorrect.

    This exception is raised when the provided sample value does not meet the expected criteria
    for correctness according to BIDS (Brain Imaging Data Structure) specifications.
    """

    def __init__(
        self, sample: object, msg: str = "Property 'sample' MUST be an integer"
    ) -> None:
        """Initialize the SampleError instance.

        Parameters
        ----------
        sample : object
            The sample value that caused the error.
        msg : str, optional
            Explanation of the error.
        """
        self.sample = sample
        self.msg = msg
        super().__init__(self.msg)

    def __str__(self) -> str:
        """Return a string representation of the error.

        Returns
        -------
        str
            A string containing the sample value and the error message.
        """
        return f"{self.sample} -> {self.msg}"

__init__(sample, msg="Property 'sample' MUST be an integer")

Initialize the SampleError instance.

Parameters:

Name Type Description Default
sample object

The sample value that caused the error.

 required
msg str

Explanation of the error.

 "Property 'sample' MUST be an integer"
Source code in psychopy_bids/bids/bidserror.py 
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def __init__(
    self, sample: object, msg: str = "Property 'sample' MUST be an integer"
) -> None:
    """Initialize the SampleError instance.

    Parameters
    ----------
    sample : object
        The sample value that caused the error.
    msg : str, optional
        Explanation of the error.
    """
    self.sample = sample
    self.msg = msg
    super().__init__(self.msg)

__str__()

Return a string representation of the error.

Returns:

Type Description
str

A string containing the sample value and the error message.
Source code in psychopy_bids/bids/bidserror.py 
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def __str__(self) -> str:
    """Return a string representation of the error.

    Returns
    -------
    str
        A string containing the sample value and the error message.
    """
    return f"{self.sample} -> {self.msg}"

ResponseTimeError

Bases: BIDSError

Exception raised when response_time value is incorrect.

This exception is raised when the provided response_time value does not meet the expected criteria for correctness according to BIDS (Brain Imaging Data Structure) specifications.

Source code in psychopy_bids/bids/bidserror.py 
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class ResponseTimeError(BIDSError):
    """Exception raised when response_time value is incorrect.

    This exception is raised when the provided response_time value does not meet the expected
    criteria for correctness according to BIDS (Brain Imaging Data Structure) specifications.
    """

    def __init__(
        self,
        response_time: object,
        msg: str = "Property 'response_time' MUST be a number (or n/a if unavailable)",
    ) -> None:
        """Initialize the ResponseTimeError instance.

        Parameters
        ----------
        response_time : object
            The response_time value that caused the error.
        msg : str, optional
            Explanation of the error.
        """
        self.response_time = response_time
        self.msg = msg
        super().__init__(self.msg)

    def __str__(self) -> str:
        """Return a string representation of the error.

        Returns
        -------
        str
            A string containing the response_time value and the error message.
        """
        return f"{self.response_time} -> {self.msg}"

__init__(response_time, msg="Property 'response_time' MUST be a number (or n/a if unavailable)")

Initialize the ResponseTimeError instance.

Parameters:

Name Type Description Default
response_time object

The response_time value that caused the error.

 required
msg str

Explanation of the error.

 "Property 'response_time' MUST be a number (or n/a if unavailable)"
Source code in psychopy_bids/bids/bidserror.py 
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def __init__(
    self,
    response_time: object,
    msg: str = "Property 'response_time' MUST be a number (or n/a if unavailable)",
) -> None:
    """Initialize the ResponseTimeError instance.

    Parameters
    ----------
    response_time : object
        The response_time value that caused the error.
    msg : str, optional
        Explanation of the error.
    """
    self.response_time = response_time
    self.msg = msg
    super().__init__(self.msg)

__str__()

Return a string representation of the error.

Returns:

Type Description
str

A string containing the response_time value and the error message.
Source code in psychopy_bids/bids/bidserror.py 
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def __str__(self) -> str:
    """Return a string representation of the error.

    Returns
    -------
    str
        A string containing the response_time value and the error message.
    """
    return f"{self.response_time} -> {self.msg}"

HedError

Bases: BIDSError

Exception raised when hed value is incorrect.

This exception is raised when the provided hed value does not meet the expected criteria for correctness according to BIDS (Brain Imaging Data Structure) specifications.

Source code in psychopy_bids/bids/bidserror.py 
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class HedError(BIDSError):
    """Exception raised when hed value is incorrect.

    This exception is raised when the provided hed value does not meet the expected criteria
    for correctness according to BIDS (Brain Imaging Data Structure) specifications.
    """

    def __init__(
        self, hed: object, msg: str = "Property 'hed' MUST be a string"
    ) -> None:
        """Initialize the HEDError instance.

        Parameters
        ----------
        hed : object
            The hed value that caused the error.
        msg : str, optional
            Explanation of the error.
        """
        self.hed = hed
        self.msg = msg
        super().__init__(self.msg)

    def __str__(self) -> str:
        """Return a string representation of the error.

        Returns
        -------
        str
            A string containing the hed value and the error message.
        """
        return f"{self.hed} -> {self.msg}"

__init__(hed, msg="Property 'hed' MUST be a string")

Initialize the HEDError instance.

Parameters:

Name Type Description Default
hed object

The hed value that caused the error.

 required
msg str

Explanation of the error.

 "Property 'hed' MUST be a string"
Source code in psychopy_bids/bids/bidserror.py 
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def __init__(
    self, hed: object, msg: str = "Property 'hed' MUST be a string"
) -> None:
    """Initialize the HEDError instance.

    Parameters
    ----------
    hed : object
        The hed value that caused the error.
    msg : str, optional
        Explanation of the error.
    """
    self.hed = hed
    self.msg = msg
    super().__init__(self.msg)

__str__()

Return a string representation of the error.

Returns:

Type Description
str

A string containing the hed value and the error message.
Source code in psychopy_bids/bids/bidserror.py 
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def __str__(self) -> str:
    """Return a string representation of the error.

    Returns
    -------
    str
        A string containing the hed value and the error message.
    """
    return f"{self.hed} -> {self.msg}"

StimFileError

Bases: BIDSError

Exception raised when stim_file value is incorrect.

This exception is raised when the provided stim_file value does not meet the expected criteria for correctness according to BIDS (Brain Imaging Data Structure) specifications.

Source code in psychopy_bids/bids/bidserror.py 
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class StimFileError(BIDSError):
    """Exception raised when stim_file value is incorrect.

    This exception is raised when the provided stim_file value does not meet the expected criteria
    for correctness according to BIDS (Brain Imaging Data Structure) specifications.
    """

    def __init__(
        self, stim_file: object, msg: str = "Property 'stim_file' MUST be a string"
    ) -> None:
        """Initialize the StimFileError instance.

        Parameters
        ----------
        stim_file : object
            The stim_file value that caused the error.
        msg : str, optional
            Explanation of the error.
        """
        self.stim_file = stim_file
        self.msg = msg
        super().__init__(self.msg)

    def __str__(self) -> str:
        """Return a string representation of the error.

        Returns
        -------
        str
            A string containing the stim_file value and the error message.
        """
        return f"{self.stim_file} -> {self.msg}"

__init__(stim_file, msg="Property 'stim_file' MUST be a string")

Initialize the StimFileError instance.

Parameters:

Name Type Description Default
stim_file object

The stim_file value that caused the error.

 required
msg str

Explanation of the error.

 "Property 'stim_file' MUST be a string"
Source code in psychopy_bids/bids/bidserror.py 
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def __init__(
    self, stim_file: object, msg: str = "Property 'stim_file' MUST be a string"
) -> None:
    """Initialize the StimFileError instance.

    Parameters
    ----------
    stim_file : object
        The stim_file value that caused the error.
    msg : str, optional
        Explanation of the error.
    """
    self.stim_file = stim_file
    self.msg = msg
    super().__init__(self.msg)

__str__()

Return a string representation of the error.

Returns:

Type Description
str

A string containing the stim_file value and the error message.
Source code in psychopy_bids/bids/bidserror.py 
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def __str__(self) -> str:
    """Return a string representation of the error.

    Returns
    -------
    str
        A string containing the stim_file value and the error message.
    """
    return f"{self.stim_file} -> {self.msg}"

IdentifierError

Bases: BIDSError

Exception raised when identifier value is incorrect.

This exception is raised when the provided identifier value does not meet the expected criteria for correctness according to BIDS (Brain Imaging Data Structure) specifications.

Source code in psychopy_bids/bids/bidserror.py 
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class IdentifierError(BIDSError):
    """Exception raised when identifier value is incorrect.

    This exception is raised when the provided identifier value does not meet the expected criteria
    for correctness according to BIDS (Brain Imaging Data Structure) specifications.
    """

    def __init__(
        self, identifier: object, msg: str = "Property 'identifier' MUST be a string"
    ) -> None:
        """Initialize the IdentifierError instance.

        Parameters
        ----------
        identifier : object
            The identifier value that caused the error.
        msg : str, optional
            Explanation of the error.
        """
        self.identifier = identifier
        self.msg = msg
        super().__init__(self.msg)

    def __str__(self) -> str:
        """Return a string representation of the error.

        Returns
        -------
        str
            A string containing the identifier value and the error message.
        """
        return f"{self.identifier} -> {self.msg}"

__init__(identifier, msg="Property 'identifier' MUST be a string")

Initialize the IdentifierError instance.

Parameters:

Name Type Description Default
identifier object

The identifier value that caused the error.

 required
msg str

Explanation of the error.

 "Property 'identifier' MUST be a string"
Source code in psychopy_bids/bids/bidserror.py 
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def __init__(
    self, identifier: object, msg: str = "Property 'identifier' MUST be a string"
) -> None:
    """Initialize the IdentifierError instance.

    Parameters
    ----------
    identifier : object
        The identifier value that caused the error.
    msg : str, optional
        Explanation of the error.
    """
    self.identifier = identifier
    self.msg = msg
    super().__init__(self.msg)

__str__()

Return a string representation of the error.

Returns:

Type Description
str

A string containing the identifier value and the error message.
Source code in psychopy_bids/bids/bidserror.py 
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def __str__(self) -> str:
    """Return a string representation of the error.

    Returns
    -------
    str
        A string containing the identifier value and the error message.
    """
    return f"{self.identifier} -> {self.msg}"

DatabaseError

Bases: BIDSError

Exception raised when database value is incorrect.

This exception is raised when the provided database value does not meet the expected criteria for correctness according to BIDS (Brain Imaging Data Structure) specifications.

Source code in psychopy_bids/bids/bidserror.py 
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class DatabaseError(BIDSError):
    """Exception raised when database value is incorrect.

    This exception is raised when the provided database value does not meet the expected criteria
    for correctness according to BIDS (Brain Imaging Data Structure) specifications.
    """

    def __init__(
        self, database: object, msg: str = "Property 'database' MUST be a string"
    ) -> None:
        """Initialize the DatabaseError instance.

        Parameters
        ----------
        database : object
            The database value that caused the error.
        msg : str, optional
            Explanation of the error.
        """
        self.database = database
        self.msg = msg
        super().__init__(self.msg)

    def __str__(self) -> str:
        """Return a string representation of the error.

        Returns
        -------
        str
            A string containing the database value and the error message.
        """
        return f"{self.database} -> {self.msg}"

__init__(database, msg="Property 'database' MUST be a string")

Initialize the DatabaseError instance.

Parameters:

Name Type Description Default
database object

The database value that caused the error.

 required
msg str

Explanation of the error.

 "Property 'database' MUST be a string"
Source code in psychopy_bids/bids/bidserror.py 
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def __init__(
    self, database: object, msg: str = "Property 'database' MUST be a string"
) -> None:
    """Initialize the DatabaseError instance.

    Parameters
    ----------
    database : object
        The database value that caused the error.
    msg : str, optional
        Explanation of the error.
    """
    self.database = database
    self.msg = msg
    super().__init__(self.msg)

__str__()

Return a string representation of the error.

Returns:

Type Description
str

A string containing the database value and the error message.
Source code in psychopy_bids/bids/bidserror.py 
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def __str__(self) -> str:
    """Return a string representation of the error.

    Returns
    -------
    str
        A string containing the database value and the error message.
    """
    return f"{self.database} -> {self.msg}"