model.py

class Model:
    """ pm.Model decorator. """

    def __init__(self, func):
        self.func = func

        # Introspect wrapped function, instead of the decorator class.
        functools.update_wrapper(self, func)

        # Uncompile wrapped function.
        uncompiled = uncompile(func.__code__)

        # Parse AST and modify it.
        tree = parse_snippet(*uncompiled)
        tree = FunctionToGenerator().visit(tree)
        uncompiled[0] = tree

        # Recompile wrapped function.
        self.recompiled = recompile(*uncompiled)    
        
        # Execute recompiled code (defines `_pm_compiled_model_generator`)
        # in the locals() namespace and assign it to an attribute.
        # Refer to http://lucumr.pocoo.org/2011/2/1/exec-in-python/
        exec(self.recompiled, None, locals())
        self.model_generator = locals()["_pm_compiled_model_generator"]