A module is a file containing Python definitions and statements. The file name is the module name with the suffix .py appended.
The following is saved in fibo.py:
def fib(n):
a, b = 0, 1
for i in range(n):
a, b = b, a + b
return a
def fiblist(n):
fib = [0,1]
for i in range(1,n):
fib += [fib[-1]+fib[-2]]
return fib