code: def element_should_exist(self, json_string, expr):
          
          value = self.select_elements(json_string, expr)
          if value is None:
              raise JsonValidatorError('Elements %s does not exist' % expr)
docs: Check the existence of one or more elements, matching [ http://jsonselect.org/ | JSONSelect] expression.
  
          *DEPRECATED* JSON Select query language is outdated and not supported any more.
          Use other keywords of this library to query JSON.
  
          *Args:*\n
          _json_string_ - JSON string;\n
          _expr_ - JSONSelect expression;\n
  
          *Raises:*\n
          JsonValidatorError
  
          *Example:*\n
          | *Settings* | *Value* |
          | Library    | JsonValidator |
          | Library    | OperatingSystem |
          | *Test Cases* | *Action* | *Argument* | *Argument* |
          | Check element | ${json_example}=   | OperatingSystem.Get File |   ${CURDIR}${/}json_example.json |
          | | Element should exist  |  ${json_example}  |  .author:contains("Evelyn Waugh") |
          | | Element should exist  |  ${json_example}  |  .store .book  .price:expr(x=8.95) |