code: def get_checker_executable(name):
      
      if programs.is_program_installed(name):
          # Checker is properly installed
          return [name]
      else:
          path1 = programs.python_script_exists(package=None,
                                                module=name+'_script')
          path2 = programs.python_script_exists(package=None, module=name)
          if path1 is not None:  # checker_script.py is available
              # Checker script is available but has not been installed
              # (this may work with pyflakes)
              return [sys.executable, path1]
          elif path2 is not None:  # checker.py is available
              # Checker package is available but its script has not been
              # installed (this works with pycodestyle but not with pyflakes)
              return [sys.executable, path2]
docs: Return checker executable in the form of a list of arguments
      for subprocess.Popen