Show's how to use Python's dict to simulate a switch satement.

tick.py

#!/bin/env/python

import numpy as np 

def action1(t, dt):
    print t, "Action 1"

def action2(t, dt):
    print t, "Action 2"

def action3(t, dt):
    print t, "Action 3"

def action4(t, dt):
    print t, "Action 4"

def tick(t, dt):
    """
    Create a dictionary called script, with the keys being
    the times we want to call an action. The values are 
    references to the funct ions we want to call. 
    script is a (key, value) store of (time, function)
    When this function is called, a time, we check to 
    see if t is in the script, if it is we get the value
    by using script[t] and then call the function using
    the calling mechanism script[t](t, dt)
    """
    script = {
        10.0 : action1,
        15.0 : action2,
        20.0 : action3,
        27.0 : action4
    }
    if t in script:
        script[t](t, dt)

def main():
    t1, t2, dt = (0.0, 30.0, 0.1)
    for t in np.arange(t1, t2, dt):
        tick(t, dt)

if __name__ == '__main__':
    main()