Fix pep8

Author: thoo

pandas/core/generic.py

@@ -4952,7 +4952,8 @@ def pipe(self, func, *args, **kwargs):
     -------
     DataFrame, Series or scalar
         - If DataFrame.agg is called with a single function, returns a Series.
-        - If DataFrame.agg is called with several functions, returns a DataFrame.
+        - If DataFrame.agg is called with several functions, returns
+          a DataFrame.
         - If Series.agg is called with single function, returns a scalar.
         - If Series.agg is called with several functions, returns a Series.