# File lib/action_mailer/vendor/tmail-1.2.3/tmail/net.rb, line 118 def mime_encode_multipart( top = true ) self.mime_version = '1.0' if top self.set_content_type 'multipart', 'mixed' e = encoding(nil) if e and not /\A(?:7bit|8bit|binary)\z/i === e raise ArgumentError, 'using C.T.Encoding with multipart mail is not permitted' end end