Suggestion on Attributes in Pandas
This is a suggestion and not an issue.

Pandas adds the column names as attributes of the Dataframe which is quite useful in selecting a series from a Dataframe.

Suggestion scenario:

Current Output
When a new column is added, the new column name is automatically added as an attribute (Desired Result), but the old column name still remains as an attribute of that Dataframe (Undesired Result)

Suggestional Output
When a new column is added, the new column name is automatically added as an attribute (Desired Result), but the old column name should be removed from being an attribute of that Dataframe as the column no longer exists (Desired Result)

Eg:
if the column name (colour) of a dataframe (df) is renamed to color, we should have only df.color as an attribute and df.colour should be removed (deleted from being an attribute for that dataframe ) on the rename column event