    # File lib/merb-core/bootloader.rb, line 979
        def remove_classes_in_file(file, &block)
          Merb.klass_hashes.each { |x| x.protect_keys! }
          if klasses = LOADED_CLASSES.delete(file)
            klasses.each { |klass| remove_constant(klass) unless klass.to_s =~ /Router/ }
          end
          yield file if block_given?
          Merb.klass_hashes.each {|x| x.unprotect_keys!}
          nil
        end