Simple Python solution for g()('al') challenge

goal.py

#!/usr/bin/env python3

class G(object):
    def __init__(self, prefix='g'):
        self.prefix = prefix

    def __call__(self, args=None):
        if args == 'al':
            return self.prefix + 'al'
        else:
            return G(self.prefix+'o')

if __name__ == '__main__':
    g = G()
    print(g('al'))
    print(g()('al'))
    print(g()()('al'))