Code objects are used by the implementation to represent
``pseudo-compiled'' executable Python code such as a function body.
They differ from function objects because they don't contain a
reference to their global execution environment. Code objects are
returned by the built-in compile() function and can be
extracted from function objects through their func_code
attribute.
A code object can be executed or evaluated by passing it (instead of a
source string) to the exec statement or the built-in
eval() function.
