anchor.diff:  
   set TAG=[tt]
   set REQS=%CD%\reqs
  -set DEVREQS=%REQS%\requirements-dev.txt
  +set DEVREQS="%REQS%\requirements-dev.txt"
   set TT_PYPI_NAME=ttable
   
   if /I "%~1"=="" call :_help & exit /b
  
positive.code: @echo.
  @echo %TAG% Installing tt...
  pip install --upgrade --editable . >nul 2>&1
  where tt || @echo Installation of tt failed & exit /b 1
  @echo %TAG% OK.
  @echo.
  exit /b
  
negative.code: rem # An initial check to make sure that the environment is good for testing/publishing purposes.
  rem # Checks that Python 3 is being run and that a virtualenv is active.
  @echo %TAG% Asserting Python 3 is the active Python...
  python --version | findstr 3.* >nul 2>&1 || (@echo %TAG% Python 3 is not active. & exit /b 1)
  @echo %TAG% OK.
  @echo.
  @echo %TAG% Asserting a virtualenv is active...
  python -c "import sys; print(hasattr(sys, 'real_prefix'))" | findstr /I true >nul 2>&1 || (@echo %TAG% Not running inside virtualenv. & exit /b 1)
  @echo %TAG% OK.
  exit /b
  
  