replace with a 'virtual' pump, which kicks off any other nodes with no incoming nodes
the virtual pump, called by a rewritten 'execute'
execute tests if the incoming param is a generator or a value, if it's a value it calls inner_execute, if it's a generator, it iterates through the values calling inner_execute
replace with a 'virtual' pump, which kicks off any other nodes with no incoming nodes
the virtual pump, called by a rewritten 'execute'
execute tests if the incoming param is a generator or a value, if it's a value it calls inner_execute, if it's a generator, it iterates through the values calling inner_execute
execute sets the tracing on the messages