class Rake::Application

def deprecate(old_usage, new_usage, call_site) # :nodoc:

:nodoc:

Rake.application.deprecate("import", "Rake.import", caller.first)
Example:

Warn about deprecated usage. 
def deprecate(old_usage, new_usage, call_site) # :nodoc:
  unless options.ignore_deprecate
    $stderr.puts "WARNING: '#{old_usage}' is deprecated.  " +
      "Please use '#{new_usage}' instead.\n" +
      "    at #{call_site}"
  end
end