code: def replaced(self, contents):
          
          line_num = len(contents.strip(' ').splitlines())
          replace_marks = self.RE_REPLACE_MARK.findall(contents.strip())
          if len(replace_marks) == line_num:
              return False
          return True
docs: For a question snippet containing some default code, return True if the
          default code is replaced. Default code in a snippet should have
          '\# Replace with your solution' at the end of each line.