def unquote_as_string(s, charset=None):
    if charset is None:
        charset = "UTF-8"
    return str(unquote(s), charset, 'strict')

def unquote(s):
    """unquote('abc%20def') -> 'abc def'."""
    res = s.split('%')
    res[0] = res[0].encode('ASCII', 'strict')
    for i in range(1, len(res)):
        res[i] = (bytes.fromhex(res[i][:2]) +
                  res[i][2:].encode('ASCII', 'strict')
    return b''.join(res)

def unquote_plus(s):
    """unquote('%7e/abc+def') -> '~/abc def'"""
    s = s.replace('+', ' ')
    return unquote(s)

always_safe = (b'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
               b'abcdefghijklmnopqrstuvwxyz'
               b'0123456789'
               b'_.-')

percent_code = ord('%')

hextable = b'0123456789ABCDEF'

def quote(s, safe = '/', plus=False):
    """quote(b'abc@def') -> 'abc%40def'"""

    if isinstance(s, str):
        s = s.encode("UTF-8", "strict")
    if not (isinstance(s, bytes) or isinstance(s, bytearray)):
        raise ValueError("Argument to quote must be either bytes "
                         "or bytearray; string arguments will be "
                         "converted to UTF-8 bytes")
    safeset = always_safe + safe.encode('ASCII', 'strict')
    result = bytearray()
    for i in s:
        if i not in safeset:
            result.append(percent_code)
            result.append(hextable[(i >> 4) & 0xF])
            result.append(hextable[i & 0xF])
        else:
            result.append(i)
    return str(result, 'ASCII', 'strict')