def method_missing(name, *args, &block)
      helpers.key?(name) ? helpers.fetch(name).call : super
    end
def method_missing(name, *args, &block)
      helpers.key?(name) ? helpers.fetch(name).call : super
    end
Override Ruby's method_missing in order to provide `On#let` interface.

 @api private

 @since 0.11.0

 @raise [NoMethodError] If doesn't respond to the given method.