code: def _load_rule_file(self, filename):
          
          if not (os.path.exists(filename)):
              sys.stderr.write("rflint: %s: No such file or directory\n" % filename)
              return
          try:
              basename = os.path.basename(filename)
              (name, ext) = os.path.splitext(basename)
              imp.load_source(name, filename)
          except Exception as e:
              sys.stderr.write("rflint: %s: exception while loading: %s\n" % (filename, str(e)))
docs: Import the given rule file