code: public <T extends Table> T setHeaders(boolean strictPosition, final String... headers) {
          List<WebLocator> list = new ArrayList<>();
          for (int i = 0; i < headers.length; i++) {
              WebLocator headerEL = new WebLocator(this).setClasses("x-column-header").
                      setText(headers[i], SearchType.DEEP_CHILD_NODE_OR_SELF, SearchType.EQUALS);
              if (strictPosition) {
                  headerEL.setTag("*[" + (i + 1) + "]");
              }
              list.add(headerEL);
          }
          setChildNodes(list.toArray(new WebLocator[0]));
          return (T) this;
      }
docs: <pre>{@code
  Grid grid = new Grid().setHeaders(true, "Company", "Price", "Change");
  }</pre>
  
  @param strictPosition true if grid's headers is order
  @param headers        grid's headers in order, if grid has no header put empty string
  @param <T>            element which extended the Table
  @return this Grid