require_library_or_gem (Kernel)

    # File lib/active_support/core_ext/kernel/requires.rb, line 4
      def require_library_or_gem(library_name)
        silence_warnings do
          begin
            require library_name
          rescue LoadError => cannot_require
            # 1. Requiring the module is unsuccessful, maybe it's a gem and nobody required rubygems yet. Try.
            begin
              require 'rubygems'
            rescue LoadError => rubygems_not_installed
              raise cannot_require
            end
            # 2. Rubygems is installed and loaded. Try to load the library again
            begin
              require library_name
            rescue LoadError => gem_not_installed
              raise cannot_require
            end
          end
        end
      end