def __init__(self):
        """Create objects to help during execution."""
        ### create a map to store input for parameters
        ### (the input comes only from other nodes)
        self.argument_map = {}

        ### create set to store ids of nodes providing incoming
        ### connections (inputs) to this one;
        ###
        ### also store references to recurrent methods

        isi = self.input_source_ids = set()

        self.clear_source_ids = isi.clear
        self.remove_source_ids = isi.difference_update
        self.add_source_id = isi.add

        ### set an empty function as the 'perform_pre_execution_setups'
        ### routine
        self.perform_pre_execution_setups = empty_function
Create objects to help during execution.
nodezator/graphman/operatornode/execution.py