module ActiveAdmin::Filters::DSL

def filter(attribute, options = {})

For docs, please see ActiveAdmin::Filters::ResourceExtension#add_filter 
def filter(attribute, options = {})
  config.add_filter(attribute, options)
end

def preserve_default_filters!

For docs, please see ActiveAdmin::Filters::ResourceExtension#preserve_default_filters! 
def preserve_default_filters!
  config.preserve_default_filters!
end

def remove_filter(*attributes)

For docs, please see ActiveAdmin::Filters::ResourceExtension#remove_filter 
def remove_filter(*attributes)
  config.remove_filter(*attributes)
end