''' Q7: Given lists a, b as input, append list b to list a and return the appended list.
>>> f([1,2,3,4], [1,2,3,4])
[1,2,3,4,1,2,3,4]
>>> f(['a','b','c'], ['d', 'e', 'f'])
['a','b','c','d','e','f']
>>> f([],['a'])
['a']
>>>f([[]],[b])
[[],'b']
'''
def f(a,b):
    # Your Code Here!
    pass

if __name__ == '__main__':
    import doctest
    doctest.testmod()