code: public boolean contains(Mention mention)
      {
          return sentence.equals(mention.sentence) && start <= mention.start && end >= mention.end;
      }
docs: Determines whether this {@link Mention} contains the specified {@link Mention}
  
  @param mention
  @return <code>true</code> if this {@link Mention} contains the specified {@link Mention}, <code>false</code> otherwise