code: def parse_pseudo_contains(self, sel, m, has_selector):
          
  
          values = m.group('values')
          patterns = []
          for token in RE_VALUES.finditer(values):
              if token.group('split'):
                  continue
              value = token.group('value')
              if value.startswith(("'", '"')):
                  value = css_unescape(value[1:-1], True)
              else:
                  value = css_unescape(value)
              patterns.append(value)
          sel.contains.append(ct.SelectorContains(tuple(patterns)))
          has_selector = True
          return has_selector
docs: Parse contains.