code: function checkSearchTerm(searchTerm){
  		if (!is_string(searchTerm) && !is_numeric(searchTerm)){
  			console.log('\nError: This must be either a string or an interval:\n', searchTerm, ' \n');
  			return false;
  		} else {
  			return true;
  		}
  	}
docs: Throw an error if neither a string or an interval provided