:
    return s[0] in '\'"' or (s[0] in 'rRuU' and s[1] in '\'"')


def safe_eval(s):
    # unwrap quotes, safely
    return eval(s, {'__builtins__':{}}, {})


def normalize(s, encoding):
    # This converts the various Python string types into a format that is
    # appropriate for .po files, namely much closer to C style.
    lines = s.split('\n')
    if len(lines) == 1:
        s = '"' + escape(s, encoding) + '"'
    else:
        if not lines[-1]:
            del lines[-1]
            lines[-1] = lines[-1] + '\n'
        for i in range(len(lines)):
            lines[i] = escape(lines[i], encoding)
        lineterm = '\\n"\n"'
        s = '""\n"' + lineterm.join(lines) + '"'
    return s