Circular dependency in Python

You may not need to import Path in node.py in order for Path and Node to make use of one another.

# in __init__.py  (The order of imports should not matter.)
from .node import Node
from .path import Path

# in path.py 
from . import Node
class Path
  ...

  def return_something_pathy(self): 
    ...

# in node.py
class Node
  def __init__(self, path): 
    self.path = path
    ...

  def a_node_method():
    print(self.path.return_something_pathy())

To make it clear that Node is making use of Path, add type hinting. There is a feature available starting with Python 3.7 to support forward references in type annotations, described in PEP 563.

# in node.py  (Now with type hinting.)
from __future__ import annotations

class Node
  def __init__(self, path: Path): 
    self.path = path
    ...

  def a_node_method():
    print(self.path.return_something_pathy())

I came across a Yet another solution to dig you out of a circular import hole in Python is a great blog post which taught me this.

Importing Python Modules is a great article that explains circular imports in Python.

The easiest way to fix this is to move the path import to the end of the node module.

One other approach is importing one of the two modules only in the function where you need it in the other. Sure, this works best if you only need it in one or a small number of functions:

# in node.py 
from path import Path
class Node 
    ...

# in path.py
class Path
  def method_needs_node(): 
    from node import Node
    n = Node()
    ...