在isinstance中仅使用类名而不使用名称空间

Question

This works in a script to recognise if a is of class myproject.aa.RefClass

isinstance(a, myproject.aa.RefClass)

But how could I do it so I do not have to specify the full namespace ? I would like to be able to type:

isinstance(a, RefClass)

How is this done in Python ?

EDIT: let me give more details.

In module aa.referencedatatable.py:

class ReferenceDataTable(object):
    def __init__(self, name):
        self.name = name

    def __call__(self, f):
        self._myfn = f
        return self

def referencedatatable_from_tag(tag):
    import definitions
    defn_lst = [definitions]
    for defn in defn_lst:
        referencedatatable_instance_lst = [getattr(defn, a) for a in dir(defn) if isinstance(getattr(defn, a), ReferenceDataTable)]
        for referencedatatable_instance in referencedatatable_instance_lst
            if referencedatatable_instance.name == tag
                return referencedatatable_instance
    raise("could not find")

def main()
    referencedata_from_tag("Example")

In module aa.definitions.py:

from aa.referencedatatable import ReferenceDataTable

@ReferenceDataTable("Example")
def EXAMPLE():
    raise NotImplementedError("not written")

For some reason calling the main from aa.referencedatatable.py will throw as it will not be able to recognise the instance of the class. But if I copy this main in another module it will work:

import aa.referencedatatable

a = aa.referencedatatable.referencedatatable_from_tag("Example")
print a

This second example works, for some reason calling this function inside the same module where the class is declared does not.

Answer 1

The 'namespace' is just a module object, and so is the class. You can always assign the class to a different name:

RefClass = myproject.aa.RefClass

or better yet, import it directly into your own namespace:

from myproject.aa import RefClass

Either way, now you have a global name RefClass that references the class object, so you can do:

isinstance(a, RefClass)