I use venv module to make a virtual environment in cpython3.6.
After it, I try to activate it with fish, but it give me an error, like the screenshot. 
I open the activate.fish and remove the $ sign in line 58 and 59, then the activate file works. 
I open the activate.fish of py3.5 venv, there isn't a $ sign in line 58 and 59, too. 
However, there is a bug issue which add the $ in front of the prompt. 
I'm not sure how this happen, but I think there should not be a $ there.