code: def wait_until_page_contains_element(self, locator, timeout=None, error=None):
          
          if not error:
              error = "Element '%s' did not appear in <TIMEOUT>" % locator
          self._wait_until(timeout, error, self._is_element_present, locator)
docs: Waits until element specified with `locator` appears on current page.
  
          Fails if `timeout` expires before the element appears. See
          `introduction` for more information about `timeout` and its
          default value.
  
          `error` can be used to override the default error message.
  
          See also `Wait Until Page Contains`,
          `Wait Until Page Does Not Contain`
          `Wait Until Page Does Not Contain Element`
          and BuiltIn keyword `Wait Until Keyword Succeeds`.