Передаём опции в функцию

require 'pp'
def foo(opts = {})
        opts = {:key => :value, :key2 => :value2}.merge(opts)
end

pp foo 
pp foo(:bar => :baz,
       :key => :value3)

{:key=>:value, :key2=>:value2}
{:key=>:value3, :key2=>:value2, :bar=>:baz}