def _is_valid_field_name(name):
 return (name and (name == name.strip()) and (not name.startswith('_')) and ('"' not in name))

def _is_valid_field_name ( name ) : return ( name and ( name == name . strip ( ) ) and ( not name . startswith ( '_' ) ) and ( '"' not in name ) )
check that field name is valid: * cant start or end with whitespace characters * cant start with underscore * cant contain double quote (") * cant be empty .