       end
 
   Our application now requires the `MyApp` module to provide an application
-  callback. This can be done by invoking `use Application` in that module
-  and defining a `start/2` callback, for example:
+  callback. This can be done by invoking `use Application` in that module and
+  defining a `start/2` callback, for example:
 
       defmodule MyApp do
         use Application


  In Elixir (actually, in Erlang/OTP), an application is a component
  implementing some specific functionality, that can be started and stopped
  as a unit, and which can be re-used in other systems as well.

  Applications are defined with an application file named `APP.app` where
  `APP` is the APP name, usually in `underscore_case` convention. The
  application file must reside in the same `ebin` directory as the
  application's modules bytecode.

  In Elixir, Mix is responsible for compiling your source code and
  generating your application `.app` file. Furthermore, Mix is also
  responsible for configuring, starting and stopping your application
  and its dependencies. For this reason, this documentation will focus
  on the remaining aspects of your application: the application environment,
  and the application callback module.

  You can learn more about Mix compilation of `.app` files by typing
  `mix help compile.app`.

  ## Application environment

  Once an application is started, OTP provides an application environment
  that can be used to configure applications.

  Assuming you are inside a Mix project, you can edit your application
  function in the `mix.exs` file to the following:

      def application do


  It is also possible to put and delete values from the application value,
  including new values that are not defined in the environment file (although
  this should be avoided).

  In the future, we plan to support configuration files which allow
  developers to configure the environment of their dependencies.

  Keep in mind that each application is responsible for its environment.
  Do not use the functions in this module for directly accessing or modifying
  the environment of other applications (as it may lead to inconsistent
  data in the application environment).

  ## Application module callback
