def except(*keys)
      self.reject { |k,v| keys.include?(k || k.to_sym) }
    end
def except(*keys)
      self.reject { |k,v| keys.include?(k || k.to_sym) }
    end
Filter keys out of a Hash.

   { :a => 1, :b => 2, :c => 3 }.except(:a)
   => { :b => 2, :c => 3 }