Interact with process: Send data to stdin. Read data from stdout and stderr, until end-of-file is reached.
        Wait for process to terminate. The optional input argument should be a string to be sent to the
        child process, or None, if no data should be sent to the child.

        communicate() returns a tuple (stdoutdata, stderrdata).

def communicate(self, input=None):
        """
        Interact with process: Send data to stdin. Read data from stdout and stderr, until end-of-file is reached.
        Wait for process to terminate. The optional input argument should be a string to be sent to the
        child process, or None, if no data should be sent to the child.

        communicate() returns a tuple (stdoutdata, stderrdata).
        """
        stdoutdata, stderrdata = self.process.communicate(input=input)
        self._returncode = self.process.returncode
        self.set_status(self.S_DONE, "status set to Done")

        return stdoutdata, stderrdata