Returns True, if the given parameter value is an instance of either
    int, str, float or bool.

def _is_simple_type(value):
    '''
    Returns True, if the given parameter value is an instance of either
    int, str, float or bool.
    '''
    return isinstance(value, six.string_types) or isinstance(value, int) or isinstance(value, float) or isinstance(value, bool)