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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 _get_provider_sessions(self):
 """Gets list of all known provider sessions."""

        agent_key = self._get_agent_key()
        sessions = []
        for session_name in self._provider_sessions[agent_key]:
            sessions.append(self._provider_sessions[agent_key][session_name])
        return sessions