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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, n_bytes=-1):
 """Read a number of bytes from the memory. .. note:: Reads beyond the specified memory range will be truncated. .. note:: Produces a :py:exc:`.TruncationWarning` if fewer bytes are read than requested. These warnings can be converted into exceptions using :py:func:`warnings.simplefilter`:: Parameters n_bytes : int A number of bytes to read. If the number of bytes is negative or omitted then read all data until the end of memory region. Returns ------- :py:class:`bytes` Data read from SpiNNaker as a bytestring. """

        # If n_bytes is negative then calculate it as the number of bytes left
        if n_bytes < 0:
            n_bytes = self._end_address - self.address

        # Determine how far to read, then read nothing beyond that point.
        if self.address + n_bytes > self._end_address:
            new_n_bytes = self._end_address - self.address
            warnings.warn("read truncated from {} to {} bytes".format(
                n_bytes, new_n_bytes), TruncationWarning, stacklevel=3)
            n_bytes = new_n_bytes

        if n_bytes <= 0:
            return b''

        # Perform the read and increment the offset
        data = self._parent._perform_read(self.address, n_bytes)
        self._offset += n_bytes
        return data