class Mime::Mimes

def <<(type)
  @mimes << type
  @symbols = nil
end

def delete_if
  @mimes.delete_if { |x| yield x }.tap { @symbols = nil }
end

def each
  @mimes.each { |x| yield x }
end

def initialize
  @mimes = []
  @symbols = nil
end

def symbols
  @symbols ||= map(&:to_sym)
end