auto-incrementor and infinate list

ai_il.py

"""
>>> I = ai(start=0, step=1)
>>> I()
0
>>> I()
1
>>> J = ai(start=0, step=1)
>>> J()
0
>>> I()
2
>>> J()
1
"""

def infinate_list(start, step):
    # infinate list generator
    while(True):
        yield start
        start += step

def ai(start=0, step=1):
    # auto-incrementer factory function
    il = infinate_list(start, step)
    return lambda: il.next()