For loop behavior in python -

i have these 2 function calculate numbers of animals based upon input in function. want know behavior of function. if input 20 heads , 56 legs 8 pigs , 12 chickens ultimately. there questions.

 def solve(numlegs, numheads):     numchick in range(0, numheads + 1): #we have got 12 chickens here?         numpigs = numheads - numchicks         totlegs = 4 * numpigs + 2* numchicks         if totlegs == numlegs:            return [numpigs, numchicks]     return[none, none]  def barnyard():     heads = int(raw_input('enter number of heads:'))     legs = int(raw_input('enter number of legs:'))     pigs, chickens = solve(legs, heads)     if pigs = none:        print 'there no solution'     else:         print 'number of pigs:' , pigs         pirnt 'number of chickes:', chickens 

i stuck here for numchick in range(0, numheads + 1):. if number chickens in loop line can proceed calculating number of pigs right? how 12 chickens line commented above? please consider number of inputs

for numchick in range(0, numheads + 1)://what doing? 

is loop loop 0 until numheads + 1. if numheads 10, loop 0 until 10, if numheads 100, loop 0 until 100

see python loop function: https://wiki.python.org/moin/forloop

and range function: https://docs.python.org/2/library/functions.html#range

e.g.

>>> range(1, 11) [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] 

each time loops, numchick takes respective value, i.e. numchick take values starting 0: 0, 1, 2, ... , numheads