code: def _uncamelize(self, s):
          ''' Convert a camel-cased string to using underscores '''
          res = ''
          if s:
              for i in range(len(s)): 
                  if i > 0 and s[i].lower() != s[i]:
                      res += '_'
                  res += s[i].lower()
          return ref _uncamelize(self, s):
          ''' Convert a camel-cased string to using underscores '''
          res = ''
          if s:
              for i in range(len(s)): 
                  if i > 0 and s[i].lower() != s[i]:
                      res += '_'
                  res += s[i].lower()
          return res
docs: Convert a camel-cased string to using underscores