Issues

id

Do not use the variable name id. It is the name of a python built in function which returns the address of an object.

For details see ‘id’ is a bad variable name in Python

module object has no attribute

I have bumped into this error when I name a file the same as some external class I am trying to import e.g. script file name csv.py and import csv at the top of the script.

'module' object has no attribute

Note: Make sure you delete the compiled .pyc file as well!

UnboundLocalError

Python Functions: Assignments And Scope

Quite a nasty one this… here is the code which threw the exception:

cache_clear = False

class TestRunner:
    def __call__(self):
        if cache_clear:
            # do something...
            cache_clear = True

The issue here is to do with the python interpreter deciding if cache_clear is a local or global inside the __call__ method.

To solve the problem, we tell the method that cache_clear is a global variable by using the global statement to list the (global) variables:

cache_clear = False

class TestRunner:
    def __call__(self):
        global cache_clear
        if cache_clear:
            # do something...
            cache_clear = True

SyntaxError: Non-ASCII character in file, but no encoding declared

The source code contained the pound character:

SyntaxError: Non-ASCII character in file 'gateway.py', but no encoding declared;
see http://www.python.org/peps/pep-0263.html for details

To solve the issue, I put the following at the top of the source file:

# -*- coding: utf-8 -*-

Source Code Encoding

ValueError: bad marshal data (unknown type code)

When running py.test…

This is something to do with .pyc files. I tried removing them:

find . -name '*.pyc' -delete

… but this did not solve the problem.

I had a module included from a requirements file:

-e ../base

I removed the .pyc files from this app, and all was OK once more.

Might be worth removing __pycache__ folders as well if removing the pyc doesn’t help.