module Tins::Concern

def append_features(base)
  if base.instance_variable_defined?("@_dependencies")
    base.instance_variable_get("@_dependencies") << self
    false
  else
    return false if base < self
    @_dependencies.each { |dep| base.send(:include, dep) }
    super
    base.extend const_get("ClassMethods") if const_defined?("ClassMethods")
    base.class_eval(&@_included_block) if instance_variable_defined?("@_included_block")
    Thread.current[:tin_concern_args] = nil
    true
  end
end