Some docstrings

Author: palewire

postgres_copy/__init__.py

@@ -23,8 +23,10 @@ def to_csv(self, csv_path, *fields, **kwargs):
         Copy current QuerySet to CSV at provided path.
         """
         try:
+            # For Django 2.0 forward
             query = self.query.chain(CopyToQuery)
         except AttributeError:
+            # For Django 1.11 backward
             query = self.query.clone(CopyToQuery)
 
         # Get fields