code: def get_regex_strings(self, regular_expressions):
          
          str_list = []
          if regular_expressions.count is None:
              return None
          for i in self.get_strings():
              if re.match(regular_expressions, i):
                  str_list.append(i)
          return str_list
docs: Return all target strings matched the regex
  
          :param regular_expressions: the python regex
          :type regular_expressions: string
  
          :rtype: a list of strings matching the regex expression