You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mass_assignment.rb
    path of file: ./repos/activegraph/lib/active_graph/shared
    
    the code of the file until where you have to start completion: module ActiveGraph::Shared
  # MassAssignment allows you to bulk set and update attributes
  #
  # Including MassAssignment into your model gives it a set of mass assignment
  # methods, similar to those found in ActiveRecord.
  #
  # @example Usage
  #   class Person
  #     include ActiveGraph::Shared::MassAssignment
  #   end
  #
  # Originally part of ActiveAttr, https://github.com/cgriego
    
    def add_undeclared_property(_, _); end

    # Mass update a model's attributes
    #
    # @example Assigning a hash
    #   person.attributes = { :first_name => "Chris", :last_name => "Griego" }
    #   person.first_name #=> "Chris"
    #   person.last_name #=> "Griego"
    #
    # @param (see #assign_attributes)
    def attributes=(new_attributes)
      assign_attributes(new_attributes)
    end

    # Initialize a model with a set of attributes
    #
    # @example Initializing with a hash
    #   person = Person.new(:first_name => "Chris", :last_name => "Griego")
    #   person.first_name #=> "Chris"
    #   person.last_name #=> "Griego"
    #
    # @param (see #assign_attributes)
    def initialize(attributes = nil)
      assign_attributes(attributes)
      super()
    end
  end