 Python 's developers strive to avoid premature optimization , and moreover , reject patches to non @-@ critical parts of CPython that would offer a marginal increase in speed at the cost of clarity . When speed is important , a Python programmer can move time @-@ critical functions to extension modules written in languages such as C , or try using PyPy , a just @-@ in @-@ time compiler . Cython is also available , which translates a Python script into C and makes direct C @-@ level API calls into the Python interpreter . 
