How to use prune_sys_dot_modules method in Contexts

1import importlib
2import os
3import sys
4
5
6class Importer(object):
7    def initialise(self, args, env):
8        return True
9
10    def import_module(self, dir_path, module_name):
11        filename = resolve_filename(dir_path, module_name)
12        prune_sys_dot_modules(module_name, filename)
13        if module_name in sys.modules:
14            return
15
16        loader = self.get_loader(module_name, filename)
17        return loader.load_module(module_name)
18
19    def get_loader(self, module_name, filename):
20        return importlib.machinery.SourceFileLoader(module_name, filename)
21
22    def __eq__(self, other):
23        return type(self) == type(other)
24
25
26def resolve_filename(dir_path, module_name):
27    filename = os.path.join(dir_path, *module_name.split('.'))
28    if os.path.isdir(filename):  # it's a package
29        filename = os.path.join(filename, '__init__.py')
30    else:
31        filename += '.py'
32    return filename
33
34
35def prune_sys_dot_modules(module_name, module_location):
36    if module_name in sys.modules:
37        existing_module = sys.modules[module_name]
38        if not same_file(existing_module.__file__, module_location):
39            del sys.modules[module_name]
40
41
42def same_file(path1, path2):
43    return os.path.realpath(path1) == os.path.realpath(path2)
44

Source: __init__.py

import importlib
import os
import sys


class Importer(object):
    def initialise(self, args, env):
        return True

    def import_module(self, dir_path, module_name):
        filename = resolve_filename(dir_path, module_name)
        prune_sys_dot_modules(module_name, filename)
        if module_name in sys.modules:
            return

        loader = self.get_loader(module_name, filename)
        return loader.load_module(module_name)

    def get_loader(self, module_name, filename):
        return importlib.machinery.SourceFileLoader(module_name, filename)

    def __eq__(self, other):
        return type(self) == type(other)


def resolve_filename(dir_path, module_name):
    filename = os.path.join(dir_path, *module_name.split('.'))
    if os.path.isdir(filename):  # it's a package
        filename = os.path.join(filename, '__init__.py')
    else:
        filename += '.py'
    return filename


def prune_sys_dot_modules(module_name, module_location):
    if module_name in sys.modules:
        existing_module = sys.modules[module_name]
        if not same_file(existing_module.__file__, module_location):
            del sys.modules[module_name]


def same_file(path1, path2):
    return os.path.realpath(path1) == os.path.realpath(path2)