fix: use importlib_resources before python 3.9

rattail/files.py

@@ -35,11 +35,6 @@ import tempfile
 import errno
 import warnings
 
-try:
-    import importlib.resources as importlib_resources
-except ImportError:
-    import importlib_resources
-
 from rattail.exceptions import PathNotFound
 
 
@@ -222,9 +217,15 @@ def resource_path(path):
     :rtype: string
     """
     if not os.path.isabs(path) and ':' in path:
+
+        try:
+            from importlib.resources import files, as_file
+        except ImportError: # python < 3.9
+            from importlib_resources import files, as_file
+
         package, filename = path.split(':')
-        ref = importlib_resources.files(package) / filename
-        with importlib_resources.as_file(ref) as path:
+        ref = files(package) / filename
+        with as_file(ref) as path:
             return str(path)
 
     return path

setup.cfg

@@ -39,7 +39,7 @@ install_requires =
         colander
         humanize
         importlib_metadata ; python_version < '3.8'
-        importlib_resources ; python_version < '3.8'
+        importlib_resources ; python_version < '3.9'
         lockfile
         makefun
         Mako