import ast


def parse_snippet(source, filename, mode, flags, firstlineno, privateprefix_ignored=None):
    """ Like ast.parse, but accepts indented code snippet with a line number offset. """
    args = filename, mode, flags | ast.PyCF_ONLY_AST, True
    prefix = '\n'
    try:
        a = compile(prefix + source, *args)
    except IndentationError:
        # Already indented? Wrap with dummy compound statement
        prefix = 'with 0:\n'
        a = compile(prefix + source, *args)
        # peel wrapper
        a.body = a.body[0].body
    ast.increment_lineno(a, firstlineno - 2)
    return a