# File lib/versionomy/conversion.rb, line 121
      def register(from_schema_, to_schema_, conversion_, silent_=false)
        key_ = _get_key(from_schema_, to_schema_)
        @mutex.synchronize do
          if @registry.include?(key_)
            unless silent_
              raise Errors::ConversionRedefinedError
            end
          else
            @registry[key_] = conversion_
          end
        end
      end