code: def get_elem_index(self, data, starting=True):
          
          idx = len(data)
          for opt in self.opt.keys():
              i = self.get_key_index(data, opt, starting)
              if i < idx and i != -1:
                  idx = i
          if idx == len(data):
              idx = -1
          return idx
docs: Get from a docstring the next option.
          In javadoc style it could be @param, @return, @type,...
  
          :param data: string to parse
          :param starting: does the key element must start the line (Default value = True)
          :type starting: boolean
          :returns: index of found element else -1
          :rtype: integer