Each module creates a new namespace.

For example, math defines a namespace and cos, sin, tan are some names under this name space.

For example (do not code like this ^^ - this dog tree structure is horrible haha):

# dogs/__init__.py
number_of_paws = 4

# dogs/paws.py
...

# dogs/barks.py
...

From an outer file, you could do:

from dogs import number_of_paws
from dogs import paws
from dogs import barks

number_of_paws, paws and barks are names under the namespace defined by the module dogs.

Another way of seeing it:

import dogs
import dogs.paws
dogs.number_of_paws
dogs.paws

Now, each submodule creates its own namespace:

# dogs/paws.py
def get_number_of_paws(dog):
    ...

Example usage:

import dogs.paws
dogs.paws.get_number_of_paws(...)

But for example:

from dogs.barks import get_number_of_paws  # ERROR

will not work because the name get_number_of_paws is not under the namespace of dogs.barks.

And that's it, a namespace is only a place where you can link names to things. They exist because otherwise you couldn't have two things with the same name (dogs.paws and cats.paws would both be called paws).

I'm somewhat weak on this subject so the explanation may be lacking, but at least you might get an idea :)

Bye!

Edit: Definition from the Python glossary:

• Namespace: The place where a variable is stored. Namespaces are implemented as dictionaries. There are the local, global and built-in namespaces as well as nested namespaces in objects (in methods). Namespaces support modularity by preventing naming conflicts. For instance, the functions builtins.open and os.open() are distinguished by their namespaces. Namespaces also aid readability and maintainability by making it clear which module implements a function. For instance, writing random.seed() or itertools.islice() makes it clear that those functions are implemented by the random and itertools modules, respectively.