This is a simple bit of code that I think is ugly. I am looking for a suggestion on making it more idiomatic. Thanks!

gistfile1.rb

  def populate_todolist
		progs = @user.participating_programs
		@to_do_list = progs.map { |prog| build_todolist_row(prog) }
		@to_do_list.compact!
	end

	# return nil if analysis yields no todolist row. compact! above removes the nil.
	def build_todolist_row prog
		rounds = prog.open_rounds
		raise "more than one round open in ToDoList" if rounds.length > 1
		if rounds.length == 1
			result = ToDoListRow.with(program_name: prog.name)
		end
		return nil
	end

I would change the API of these methods a little. Resulting in the following

def populate_todolist(programs)
  @to_do_list = programs.map do |program|
    build_todolist_row(program.name, program.open_rounds)
  end
end

def build_todolist_row(program_name, rounds)
  raise "more than one round open in ToDoList" if rounds.length > 1

  ToDoListRow.with(program_name: program_name)
end