code: function replaceCharactersByIndex( text, indices, substitute ) {
  	const modifiedTextSplitByLetter = text.split( "" );
  
  	indices.forEach( function( index ) {
  		modifiedTextSplitByLetter.splice( index, 1, substitute );
  	} );
  
  	return modifiedTextSplitByLetter.join( "" );
  }
docs: Replaces characters on specified indices in the input text.
  
  @param {string} text The original text, for which the characters have to be substituted.
  @param {Array} indices The array of indices that have to be substituted.
  @param {string} substitute The character that is used to substitute in the text.
  
  @returns {string} result The string of the original text with the characters on specified indices are substituted with the substitute character.