Boris Grube

### Explain what you would like to see improved and how. The documentation for `TF3::Draw()` states: "Draw this function with its current attributes." This suggests that `TF3::Draw()` should behave similarly...

### Check duplicate issues. - [x] Checked for duplicates ### Description Creating a `TF1` from a C++ functor with the number of parameters set to zero and drawing this function...