   @hex_requirement  ">= 0.5.0"
 
   @doc """
-  Returns true if Hex is loaded or installed, otherwise returns false.
+  Returns `true` if `Hex` is loaded or installed. Otherwise returns `false`.
   """
   @spec ensure_installed?(atom) :: boolean
   def ensure_installed?(app) do

  end

  @doc """
  Returns true if have required Hex, returns false if don't and don't update,
  if update then exits.
  """
  @spec ensure_updated?() :: boolean
  def ensure_updated?() do
    cond do
      !Code.ensure_loaded?(Hex) ->
        false
      !Version.match?(Hex.version, @hex_requirement) ->
        Mix.shell.info "Mix requires hex #{@hex_requirement} but you have #{Hex.version}"

        if Mix.shell.yes?("Shall I abort the current command and update hex?") do

  end

  @doc """
  Ensures `Hex` is started.
  """
  def start do
    try do
