https://en.wikipedia.org/wiki/Squared_triangular_number

thx

That test checks if the functions are independant. It defines more than one lazy function, then calls them at intervals to make sure that each one is only affecting itself.

Example (not the real test):

@lazy(3)
def a():
    pass
  
@lazy(-2)
def b():
    pass
  
a() # Works
b() # Works
b() # Lazy
a() # Works
b() # Works

Functions a and b should each be on their own independant 'timers'.

:D