_requirements

Enforce requirements.

Classes

RequirementError

Bases: Exception

Exception raised when a requirement is not satisfied.

Source code in fgpyo/_requirements.py

class RequirementError(Exception):
    """Exception raised when a requirement is not satisfied."""

Functions

require

require(condition: bool, message: Union[str, Callable[[], str], None] = None) -> None

Require a condition be satisfied.

Parameters:

Name	Type	Description	Default
condition	bool	The condition to satisfy.	required
message	Union[str, Callable[[], str], None]	An optional message to include with the error when the condition is false. The message may be provided as either a string literal or a function returning a string. The function will not be evaluated unless the condition is false.	None

Raises:

Type	Description
RequirementError	If the condition is false.

Source code in fgpyo/_requirements.py

def require(condition: bool, message: Union[str, Callable[[], str], None] = None) -> None:
    """Require a condition be satisfied.

    Args:
        condition: The condition to satisfy.
        message: An optional message to include with the error when the condition is false.
            The message may be provided as either a string literal or a function returning a string.
            The function will not be evaluated unless the condition is false.

    Raises:
        RequirementError: If the condition is false.
    """
    if not condition:
        if message is None:
            raise RequirementError()
        elif isinstance(message, str):
            raise RequirementError(message)
        else:
            raise RequirementError(message())