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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 start_process(self, process, args=None, cwd=None, env=None):
 """ Starts a process interactively. :param process: Process to run :type process: str :param args: List of arguments (list of str) :type args: list :param cwd: Working directory :type cwd: str :param env: environment variables (dict). """

        self.setReadOnly(False)
        if env is None:
            env = {}
        if args is None:
            args = []
        if not self._running:
            self.process = QProcess()
            self.process.finished.connect(self._on_process_finished)
            self.process.started.connect(self.process_started.emit)
            self.process.error.connect(self._write_error)
            self.process.readyReadStandardError.connect(self._on_stderr)
            self.process.readyReadStandardOutput.connect(self._on_stdout)
            if cwd:
                self.process.setWorkingDirectory(cwd)
            e = self.process.systemEnvironment()
            ev = QProcessEnvironment()
            for v in e:
                values = v.split('=')
                ev.insert(values[0], '='.join(values[1:]))
            for k, v in env.items():
                ev.insert(k, v)
            self.process.setProcessEnvironment(ev)
            self._running = True
            self._process_name = process
            self._args = args
            if self._clear_on_start:
                self.clear()
            self._user_stop = False
            self._write_started()
            self.process.start(process, args)
            self.process.waitForStarted()
        else:
            _logger().warning('a process is already running')