a = {'a': '1', 'b': '2', 'c':'3'}
b = {'d': '4', 'e':'5'}

c = {'a': '1', 'b': '2', 'c':'3', 'd': '4', 'e':'5'}

def mer(dict1, dict2):
    buf = dict2.copy()
    for i,j in dict1.iteritems():
        buf[i] = j
    return buf

a = {'a': '1', 'b': '2', 'c':'3''}
b = {'d': '4', 'e':'5'}

c = dict(a.items() + b.items())