getConversationContext(session) {
    return new Promise((resolve, reject) => {
      const conversationId = this.getConversationId(session);
      if (!conversationId) {
        return reject(new Error('No conversation id found'));
      }
      if (!this.conversationContexts[conversationId]) {
        this.conversationContexts[conversationId] = {};
      }
      return resolve(this.conversationContexts[conversationId]);
    });
  }
Gets the conversation context from the session.
@param {Object} session Chatbot session of the conversation.
@returns {Promise<Object>} Promise to resolve the conversation context.