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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 read(self, num_bytes):
 """Read `num_bytes` and return them. Parameters num_bytes : int Number of bytes to extract from the underlying stream. Raises ------ UnderflowDecodeError Raised when a read failed to extract enough bytes from the underlying stream to extract the bytes. Returns ------- bytes A bytes object extracted from underlying stream. """

        buf = self.__f.read(num_bytes)
        assert len(buf) <= num_bytes
        if len(buf) < num_bytes:
            raise UnderflowDecodeError()
        self.__num_bytes_consumed += num_bytes

        return buf