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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 _GetDecrypter(self):
 """Retrieves a decrypter. Returns: Decrypter: decrypter. Raises: IOError: if the decrypter cannot be initialized. OSError: if the decrypter cannot be initialized. """

    resolver.Resolver.key_chain.ExtractCredentialsFromPathSpec(self._path_spec)

    try:
      credentials = resolver.Resolver.key_chain.GetCredentials(self._path_spec)
      return encryption_manager.EncryptionManager.GetDecrypter(
          self._encryption_method, **credentials)
    except ValueError as exception:
      raise IOError(exception)