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 7
    if amount{-1}=="3":
             ^
SyntaxError: invalid syntax