def METHOD_NAME(source: dt.DataType, target: dt.DataType, **kwargs) -> bool:
    # The null type is castable to any type, even if the target type is *not*
    # nullable.
    #
    # We handle the promotion of `null + !T -> T` at the `castable` call site.
    #
    # It might be possible to build a system with a single function that tries
    # to promote types and use the exception to indicate castability, but that
    # is a deeper refactor to be tackled later.
    #
    # See https://github.com/ibis-project/ibis/issues/2891 for the bug report
    return True