class Hermod::XmlSectionBuilder

def create_method(name, mutators, validators, options = {}, &block)

Returns nothing you should rely on

block - a block that takes the value and attributes and does any post-validation mutation on them
errors under given conditions
validators - an array of Validator::Base subclasses that are applied to the value and attributes and raise
mutators - an array of InputMutator objects (normally one) that change the value and attributes in some way
name - the name of the new method

certain options. This is used to implement all the node type methods.
and a set of validators to change and validate the input according to
Private: creates a method with a given name that uses a set of mutators 
def create_method(name, mutators, validators, options = {}, &block)
  raise DuplicateNodeError, "#{name} is already defined" if @node_order.include? name
  @node_order << name
  xml_name = options.fetch(:xml_name, name.to_s.camelize)
  @new_class.send :define_method, name do |value, attributes = {}|
    mutators.each { |mutator| value, attributes = mutator.mutate!(value, attributes, self) }
    begin
      validators.each { |validator| validator.valid?(value, attributes) }
    rescue InvalidInputError => ex
      raise InvalidInputError, "#{name} #{ex.message}"
    end
    value, attributes = instance_exec(value, attributes, &block)
    if value.present?
      nodes[name] << XmlNode.new(xml_name, value, attributes).rename_attributes(options[:attributes])
    end
  end
end