code: def file_ref(self):
          
          from metatab.util import slugify
  
          assert self.file_name is None or isinstance(self.file_name, str)
  
          if self.file_name is not None and self.row is not None:
              parts = split(self.file_name);
              return "{} {}:{} ".format(parts[-1], self.row, self.col)
          elif self.row is not None:
              return " {}:{} ".format(self.row, self.col)
          else:
              return ''
docs: Return a string for the file, row and column of the term.