def eval_in_context(self, code, app, extra_imports={}):
        
        # Drag in the migration module's locals (hopefully including models.py)
        # excluding all models from that (i.e. from modern models.py), to stop pollution
        fake_locals = dict(
            (key, value)
            for key, value in inspect.getmodule(self.cls).__dict__.items()
            if not (
                isinstance(value, type)
                and issubclass(value, models.Model)
                and hasattr(value, "_meta")
            )
        )
        
        # We add our models into the locals for the eval
        fake_locals.update(dict([
            (name.split(".")[-1], model)
            for name, model in self.models.items()
        ]))
        
        # Make sure the ones for this app override.
        fake_locals.update(dict([
            (name.split(".")[-1], model)
            for name, model in self.models.items()
            if name.split(".")[0] == app
        ]))
        
        # Ourselves as orm, to allow non-fail cross-app referencing
        fake_locals['orm'] = self
        
        # And a fake _ function
        fake_locals['_'] = lambda x: x
        
        # Datetime; there should be no datetime direct accesses
        fake_locals['datetime'] = datetime_utils
        
        # Now, go through the requested imports and import them.
        for name, value in extra_imports.items():
            # First, try getting it out of locals.
            parts = value.split(".")
            try:
                obj = fake_locals[parts[0]]
                for part in parts[1:]:
                    obj = getattr(obj, part)
            except (KeyError, AttributeError):
                pass
            else:
                fake_locals[name] = obj
                continue
            # OK, try to import it directly
            try:
                fake_locals[name] = ask_for_it_by_name(value)
            except ImportError:
                if name == "SouthFieldClass":
                    raise ValueError("Cannot import the required field '%s'" % value)
                else:
                    print("WARNING: Cannot import '%s'" % value)
        
        # Use ModelsLocals to make lookups work right for CapitalisedModels
        fake_locals = ModelsLocals(fake_locals)
        
        return eval(code, globals(), fake_locals)
Evaluates the given code in the context of the migration file.
dataset/ETHPy150Open cloudera/hue/desktop/core/ext-py/South-1.0.2/south/orm.py/_FakeORM.eval_in_context