Removed multi ops.

Change-Id: Ib812e82b873e244f78a5379ab1a1c22d72bf838d
Some Refactorings.

Change-Id: Ie6f9e942011f5e9857e4fe960c286db1723ce672
Docstrings.

Change-Id: I11fb9e20498d640126857242091379e509254603