class Diff::LCS::ContextChange

def initialize(*args)
  @action, @old_position, @old_element, @new_position, @new_element = *args
  fail "Invalid Change Action '#{@action}'" unless Diff::LCS::Change.valid_action?(@action)
  fail 'Invalid (Old) Position Type' unless @old_position.nil? or @old_position.kind_of? IntClass
  fail 'Invalid (New) Position Type' unless @new_position.nil? or @new_position.kind_of? IntClass
end