diff --git a/configurations/errors.py b/configurations/errors.py
index 7128317..cfca60e 100644
--- a/configurations/errors.py
+++ b/configurations/errors.py
@@ -1,4 +1,4 @@
-from typing import *
+from typing import TYPE_CHECKING, List, Callable
 from functools import wraps
 import sys
 import os
diff --git a/configurations/values.py b/configurations/values.py
index b44f809..73d2046 100644
--- a/configurations/values.py
+++ b/configurations/values.py
@@ -7,7 +7,7 @@ from django.core import validators
 from django.core.exceptions import ValidationError, ImproperlyConfigured
 from django.utils.module_loading import import_string
 
-from .errors import ValueRetrievalError, ValueProcessingError, ConfigurationError
+from .errors import ValueRetrievalError, ValueProcessingError
 from .utils import getargspec
 
 
@@ -311,7 +311,7 @@ class BackendsValue(ListValue):
         try:
             import_string(value)
         except ImportError as err:
-            raise ValueProcessingError(self, value)
+            raise ValueProcessingError(self, value) from err
         return value