defmodule School do
  @moduledoc """
  Simulate students in a school.

  Each student is in a grade.
  """

  @doc """
  Add a student to a particular grade in school.
  """
  @spec add(Dict.t, string, pos_integer) :: Dict.t
  def add(db, name, grade) do

  end

  @doc """
  Return the names of the students in a particular grade.
  """
  @spec grade(Dict.t, pos_integer) :: [String]
  def grade(db, grade) do

  end

  @doc """
  Sorts the school by grade and name.
  """
  @spec sort(Dict) :: Dict.t
  def sort(db) do

  end
end

defmodule School do
  @moduledoc """
  Simulate students in a school.

  Each student is in a grade.
  """

  @doc """
  Add a student to a particular grade in school.
  """
  @spec add(Dict.t, String.t, pos_integer) :: Dict.t
  def add(db, name, grade) do

  end

  @doc """
  Return the names of the students in a particular grade.
  """
  @spec grade(Dict.t, pos_integer) :: [String]
  def grade(db, grade) do

  end

  @doc """
  Sorts the school by grade and name.
  """
  @spec sort(Dict) :: Dict.t
  def sort(db) do

  end
end

Fix compiler warning for grade-test's add/3 spec
Fix compiler warning for grade-test's add/3 spec

    school.exs:11: warning: string() type use is discouraged. For character lists, use char_list() type, for strings, String.t()
        school.exs:11: School (module)

parkerl/xelixir,cezarykosko/xelixir,Egogre/xelixir,tjcelaya/xelixir,elasticdog/xelixir,wobh/xelixir,victorlcampos/xelixir,montague/xelixir,exercism/xelixir