Find the Nani's base type for a given data type.

    This is useful when Nani's data types were subclassed and the original type
    is required.

def _find_base_type(data_type):
    """Find the Nani's base type for a given data type.

    This is useful when Nani's data types were subclassed and the original type
    is required.
    """
    bases = type(data_type).__mro__
    for base in bases:
        if base in _ALL:
            return base

    return None