<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def ctype_for_encoding(self, encoding):
 """Return ctypes type for an encoded Objective-C type."""

        if encoding in self.typecodes:
            return self.typecodes[encoding]
        elif encoding[0:1] == b'^' and encoding[1:] in self.typecodes:
            return POINTER(self.typecodes[encoding[1:]])
        elif encoding[0:1] == b'^' and encoding[1:] in [CGImageEncoding,
                                                        NSZoneEncoding]:
            return c_void_p
        elif encoding[0:1] == b'r' and encoding[1:] in self.typecodes:
            return self.typecodes[encoding[1:]]
        elif encoding[0:2] == b'r^' and encoding[2:] in self.typecodes:
            return POINTER(self.typecodes[encoding[2:]])
        else:
            raise Exception('unknown encoding for %s: %s'
                            % (self.name, encoding))