Adds more file error handling and corrects a bad module reference

chalk

@@ -193,7 +193,7 @@ def build_contents_from_file(path):
         valid_path = validate_path(filepath)
         if not valid_path:
             print('Invalid file path')
-            os.exit(2)
+            sys.exit(2)
 
         with open(filepath, 'r') as f:
             content = f.read().split('\n')
@@ -201,9 +201,12 @@ def build_contents_from_file(path):
                 content.pop()
     except FileNotFoundError:
         content = []
+    except IsADirectoryError:
+        print('The given filepath is a directory')
+        sys.exit(2)
     except PermissionError:
         print('You do not have permission to read {}'.format(path))
-        os.exit(2)
+        sys.exit(2)
 
 
 # Yes No queries the user with a yes no question and returns