code: public boolean contains(int ele) {
          int idx;
  
          idx = ele >> SHIFT;
          if (idx >= data.length) {
              return false;
          }
          return (data[idx] & (1 << ele)) != 0;
      }
docs: Lookup a specific element.
  @param   ele  element to lookup
  @return  true, if ele is contained in the set