def get_activities(params = {})
      if params[:foreign_id_times]
        foreign_ids = []
        timestamps = []
        params[:foreign_id_times].each{|e|
          foreign_ids << e[:foreign_id]
          timestamps << e[:time]
        }
        params = {
          foreign_ids: foreign_ids,
          timestamps: timestamps,
        }
      end
      signature = Stream::Signer.create_jwt_token('activities', '*', @api_secret, '*')
      make_request(:get, '/activities/', signature, params)
    end
def get_activities(params = {})
      if params[:foreign_id_times]
        foreign_ids = []
        timestamps = []
        params[:foreign_id_times].each{|e|
          foreign_ids << e[:foreign_id]
          timestamps << e[:time]
        }
        params = {
          foreign_ids: foreign_ids,
          timestamps: timestamps,
        }
      end
      signature = Stream::Signer.create_jwt_token('activities', '*', @api_secret, '*')
      make_request(:get, '/activities/', signature, params)
    end
Get activities directly, via ID or Foreign ID + timestamp

 @param [Hash<:ids, :foreign_id_times>] params the request params (ids or list of <:foreign_id, :time> objects)

 @return the found activities, if any.

 @example Retrieve by activity IDs
   @client.get_activities(
     ids: [
       '4b39fda2-d6e2-42c9-9abf-5301ef071b12',
       '89b910d3-1ef5-44f8-914e-e7735d79e817'
     ]
   )

 @example Retrieve by Foreign IDs + timestamps
   @client.get_activities(
     foreign_id_times: [
       { foreign_id: 'post:1000', time: '2016-11-10T13:20:00.000000' },
       { foreign_id: 'like:2000', time: '2018-01-07T09:15:59.123456' }
     ]
   )