code: public void attribute(String expectedAttribute) {
          Set<String> attributes = checkAttribute(expectedAttribute, 0, 0);
          assertNotNull(NO_ELEMENT_FOUND, attributes);
          assertTrue("Attribute not found: element attributes of '" + String.join(",", attributes) +
                  DOES_NOT_CONTAIN + expectedAttribute + "'", attributes.contains(expectedAttribute));
      }
docs: Asserts that the element contains the provided expected attribute. If
  the element isn't present, this will constitute a failure, same as a
  mismatch. This information will be logged and recorded, with a screenshot
  for traceability and added debugging support.
  
  @param expectedAttribute - the attribute to check for