def _parse_values(values, extra=None):
coerced = list(values)<EOL>if coerced == values:<EOL><INDENT>values = coerced<EOL><DEDENT>else:<EOL><INDENT>coerced = tuple(values)<EOL>if coerced == values:<EOL><INDENT>values = list(values)<EOL><DEDENT>else:<EOL><INDENT>values = [values]<EOL><DEDENT><DEDENT>if extra:<EOL><INDENT>values.extend(extra)<EOL><DEDENT>return values<EOL>
Utility function to flatten out args.

For internal use only.

:param values: list, tuple, or str
:param extra: list or None
:return: list