$ cat fibo.py
# Fibonacci numbers module
# My Python module

def fib(n):    # write Fibonacci series up to n
    a, b = 0, 1
    while b < n:
        print b,
        a, b = b, a+b

def fib2(n): # return Fibonacci series up to n
    result = []
    a, b = 0, 1
    while b < n:
        result.append(b)
        a, b = b, a+b
    return result

##</code><code>##

$ cat runfib.py
#!/usr/bin/python
import fibo

fibo.fib(1000)
print "\n"
print fibo.fib2(100)

##</code><code>##

$ cat runfib.pl
#!/usr/bin/perl
print `./runfib.py`;

##</code><code>##

$ ./runfib.pl
1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987

[1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]