Set policy to use when connecting to servers without a known host key.

        Specifically:

        * A **policy** is a "policy class" (or instance thereof), namely some
          subclass of `.MissingHostKeyPolicy` such as `.RejectPolicy` (the
          default), `.AutoAddPolicy`, `.WarningPolicy`, or a user-created
          subclass.
        * A host key is **known** when it appears in the client object's cached
          host keys structures (those manipulated by `load_system_host_keys`
          and/or `load_host_keys`).

        :param .MissingHostKeyPolicy policy:
            the policy to use when receiving a host key from a
            previously-unknown server

def set_missing_host_key_policy(self, policy):
        """
        Set policy to use when connecting to servers without a known host key.

        Specifically:

        * A **policy** is a "policy class" (or instance thereof), namely some
          subclass of `.MissingHostKeyPolicy` such as `.RejectPolicy` (the
          default), `.AutoAddPolicy`, `.WarningPolicy`, or a user-created
          subclass.
        * A host key is **known** when it appears in the client object's cached
          host keys structures (those manipulated by `load_system_host_keys`
          and/or `load_host_keys`).

        :param .MissingHostKeyPolicy policy:
            the policy to use when receiving a host key from a
            previously-unknown server
        """
        if inspect.isclass(policy):
            policy = policy()
        self._policy = policy