public HelpText(BaseSentenceBuilder sentenceBuilder, string heading, string copyright, object options)
			: this(heading, copyright, options)
		{
			Assumes.NotNull(sentenceBuilder, "sentenceBuilder");

			_sentenceBuilder = sentenceBuilder;
		}
		/// <summary>
		/// Initializes a new instance of the <see cref="CommandLine.Text.HelpText"/> class 
		/// specifying the sentence builder.
		/// </summary>
		/// <param name="sentenceBuilder">
		/// A <see cref="BaseSentenceBuilder"/> instance.
		/// </param>
		public HelpText(BaseSentenceBuilder sentenceBuilder)
			: this()
		{
			Assumes.NotNull(sentenceBuilder, "sentenceBuilder");

			_sentenceBuilder = sentenceBuilder;
		}
		/// <summary>
		/// Initializes a new instance of the <see cref="CommandLine.Text.HelpText"/> class
		/// specifying the sentence builder and heading informations.
		/// </summary>
		/// <param name="sentenceBuilder">
		/// A <see cref="BaseSentenceBuilder"/> instance.
		/// </param>
		/// <param name="heading">
		/// A string with heading information or
		/// an instance of <see cref="CommandLine.Text.HeadingInfo"/>.
		/// </param>
		public HelpText(BaseSentenceBuilder sentenceBuilder, string heading)
			: this(heading)
		{
			Assumes.NotNull(sentenceBuilder, "sentenceBuilder");

			_sentenceBuilder = sentenceBuilder;
		}
		/// <summary>
		/// Initializes a new instance of the <see cref="CommandLine.Text.HelpText"/> class.
		/// </summary>
		public HelpText()
		{
			_preOptionsHelp = new StringBuilder(_builderCapacity);
			_postOptionsHelp = new StringBuilder(_builderCapacity);

			_sentenceBuilder = BaseSentenceBuilder.CreateBuiltIn();
		}