Not quite true.

```python
def foo(a, b):
  return a + b

globals()['foo bar'] = globals()['foo']
```

Now, it's hard to _call_ that from Python.  Might be able to call it from outside Python.  Is probably best to not declare for ourselves what Python does or does not support, leave it to declaring that we strip leading and trailing whitespace.

If we were to get into enforcing naming policy, we'd probably want to confirm that it's a valid Python identifier, per http://docs.python.org/2/reference/lexical_analysis.html#identifiers  ... but I think that what you have is correct, once we remove the internal claim in this doc (and our code comment) about what can be in a Python name.  Leave it to the Python interpreter to enforce Python policy.