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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 communicate(self, input=None, timeout=-1):
 """Communicate with the child and return its output. If *input* is provided, it is sent to the client. Concurrent with sending the input, the child's standard output and standard error are read, until the child exits. The return value is a tuple ``(stdout_data, stderr_data)`` containing the data read from standard output and standard error. """

        if self._process is None:
            raise RuntimeError('no child process')
        if timeout == -1:
            timeout = self._timeout
        output = [[], []]
        def writer(stream, data):
            offset = 0
            while offset < len(data):
                buf = data[offset:offset+4096]
                stream.write(buf)
                offset += len(buf)
            stream.close()
        def reader(stream, data):
            while True:
                if self._encoding:
                    buf = stream.read(4096)
                else:
                    buf = stream.read1()
                if not buf:
                    break
                data.append(buf)
        if self.stdin:
            fibers.spawn(writer, self.stdin, input or b'')
        if self.stdout:
            fibers.spawn(reader, self.stdout, output[0])
        if self.stderr:
            fibers.spawn(reader, self.stderr, output[1])
        self.wait(timeout)
        empty = '' if self._encoding else b''
        stdout_data = empty.join(output[0])
        stderr_data = empty.join(output[1])
        return (stdout_data, stderr_data)