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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_callback(connection_id, data_buffer, data_length_pointer):
 """ SecureTransport read callback. This is called by ST to request that data be returned from the socket. """

    wrapped_socket = None
    try:
        wrapped_socket = _connection_refs.get(connection_id)
        if wrapped_socket is None:
            return SecurityConst.errSSLInternal
        base_socket = wrapped_socket.socket

        requested_length = data_length_pointer[0]

        timeout = wrapped_socket.gettimeout()
        error = None
        read_count = 0

        try:
            while read_count < requested_length:
                if timeout is None or timeout >= 0:
                    if not util.wait_for_read(base_socket, timeout):
                        raise socket.error(errno.EAGAIN, 'timed out')

                remaining = requested_length - read_count
                buffer = (ctypes.c_char * remaining).from_address(
                    data_buffer + read_count
                )
                chunk_size = base_socket.recv_into(buffer, remaining)
                read_count += chunk_size
                if not chunk_size:
                    if not read_count:
                        return SecurityConst.errSSLClosedGraceful
                    break
        except (socket.error) as e:
            error = e.errno

            if error is not None and error != errno.EAGAIN:
                data_length_pointer[0] = read_count
                if error == errno.ECONNRESET or error == errno.EPIPE:
                    return SecurityConst.errSSLClosedAbort
                raise

        data_length_pointer[0] = read_count

        if read_count != requested_length:
            return SecurityConst.errSSLWouldBlock

        return 0
    except Exception as e:
        if wrapped_socket is not None:
            wrapped_socket._exception = e
        return SecurityConst.errSSLInternal