anchor.diff:  CALL picky --update
   )
   
  +:picky
   CALL picky
  +GOTO :EOF
   
   GOTO :EOF
positive.code: IF /i "%1" == "create" GOTO create
  IF /i "%1" == "install" GOTO create
  IF /i "%1" == "update" GOTO update
  IF %ERRORLEVEL% GEQ 1 GOTO create
  
  GOTO :EOF
  
negative.code: 
  :: if it can't be activated, create it
  :create
  CALL conda create -n %env_name% python=3.5 --file conda_versions.txt
  :: don't call pip if conda runs into trouble
  IF %ERRORLEVEL% GEQ 1 EXIT /B 2
  :: call pip if we have pip requirements
  IF exist requirements.txt (
      CALL activate %env_name%
      CALL pip install -r requirements.txt
  