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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 _RegisterProcess(self, process):
 """Registers a process with the engine. Args: process (MultiProcessBaseProcess):
 process. Raises: KeyError: if the process is already registered with the engine. ValueError: if the process is missing. """

    if process is None:
      raise ValueError('Missing process.')

    if process.pid in self._processes_per_pid:
      raise KeyError(
          'Already managing process: {0!s} (PID: {1:d})'.format(
              process.name, process.pid))

    self._processes_per_pid[process.pid] = process