pydata/pandas — pull request #1837 by lenolib (2012-09-04 13:43:34+00:00)
Title: Tiny str() fix, pandas/stats/ols.py

Fix for unexpected behaviour (TypeError: not all arguments converted during string formatting) if c is a tuple, as it can be when having collapsed the multiindex columns like df_with_tuple_columns = df_with_multiindex.columns.tolist()