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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def parse_char(self, c):
            '''input some data bytes, possibly returning a new message'''
            self.buf.extend(c)

            self.total_bytes_received += len(c)

            if self.native:
                if native_testing:
                    self.test_buf.extend(c)
                    m = self.__parse_char_native(self.test_buf)
                    m2 = self.__parse_char_legacy()
                    if m2 != m:
                        print("Native: %s\nLegacy: %s\n" % (m, m2))
                        raise Exception('Native vs. Legacy mismatch')
                else:
                    m = self.__parse_char_native(self.buf)
            else:
                m = self.__parse_char_legacy()

            if m != None:
                self.total_packets_received += 1
                self.__callbacks(m)
            else:
                # XXX The idea here is if we've read something and there's nothing left in
                # the buffer, reset it to 0 which frees the memory
                if self.buf_len() == 0 and self.buf_index != 0:
                    self.buf = bytearray()
                    self.buf_index = 0

            return m