code: def _cs_path_exists(fspath):
          
          if not os.path.exists(fspath):
              return False
          # make absolute so we always have a directory
          abspath = os.path.abspath(fspath)
          directory, filename = os.path.split(abspath)
          return filename in os.listdir(directory)
docs: Case-sensitive path existence check
  
          >>> sdist_add_defaults._cs_path_exists(__file__)
          True
          >>> sdist_add_defaults._cs_path_exists(__file__.upper())
          False