code: def get_imported_modules(cells, nb_module_name=''):
      "Finds all submodules of notebook - sorted by submodules > top level modules > manual imports. This gives notebook imports priority"
      module_names = get_top_level_modules()
      nb_imports = [match.group(1) for cell in cells for match in IMPORT_RE.finditer(cell['source']) if cell['cell_type'] == 'code']
      parts = nb_module_name.split('.')
      parent_modules = ['.'.join(parts[:(x+1)]) for x in range_of(parts)]
      all_modules = module_names + nb_imports + parent_modules
      mods = [import_mod(m, ignore_errors=True) for m in all_modules]
      return [m for m in mods if m is not None]