Checks and assigns decay function and values.
assign_decay_function(decay_function, decay_value)
A list
with the validated decay function and parameter value.
A string, the name of the decay function.
A number, the value of decay parameter.
Other assigning functions:
assign_departure()
,
assign_drop_geometry()
,
assign_max_street_time()
,
assign_max_trip_duration()
,
assign_mode()
,
assign_opportunities()
,
assign_points_input()
,
assign_shortest_path()