Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/lib/python2.7/py_compile.py", line 117, in compile
    raise py_exc
py_compile.PyCompileError:   File "/in/foo.py", line 3
    c=a+a*(1+b)+a*(1+b)2+a*(1+b)3
                       ^
SyntaxError: invalid syntax