How to check does a file imports from another file in Python

I believe python's Modulefinder will effectively solve your problem. There is a key named '__main__' in the Modulefinder().items() which holds the modules that were imported in a python file. After running the script through your project and storing the data in a way that suits your purpose, you should be good to go

What you are looking for is to find import dependencies in your package modules. You can run a static analysis on your package directory and parse the import nodes in the syntax trees (ast), and build a dependency graph. Something like below:

import os
from ast import NodeVisitor, parse
import networkx as nx

class Dependency():
    def __init__(self, root):
        self.root = root
        self.base = os.path.basename(root)
        self.dependency = nx.DiGraph()
        self.visitor = NodeVisitor()
        self.visitor.visit_ImportFrom = self.visit_ImportFrom
        
        self.current_node = None
        self.dependency.add_node = self.base
        
    def visit_ImportFrom(self, node):
        self.dependency.add_edge(node.module, self.current_node)
        self.visitor.generic_visit(node)
        
    def run(self):
        for root, dirs, files in os.walk(self.root):
            for file in files:
                full_path = os.path.join(root+os.sep, file)
                loc = full_path.split(self.root+os.sep)[1].replace(os.sep,'.')
                self.current_node = self.base+'.'+loc
                with open(full_path) as fp:
                    src = fp.read()
                    tree = parse(src)
                    self.visitor.generic_visit(tree)
                    
        dependency = {}
        for src, target in nx.dfs_edges(self.dependency):
            if src in dependency:
                dependency[src].add(target)
            else:
                dependency[src] = set([target])
                
        return dependency

For the root location of any package you want to map the import dependencies, you need to do the following then:

root = "path/to/your/src"
d = Dependency(root)
d.run()

This will return the dependency tree (as a dict). Note, we parsed only ImportFrom, you need to add Import to make it complete. Also, all imports are assumed absolute here (i.e. no .. etc). If required, you can add that too (check the level field of the ImportFrom node to do that).