Helper method to add pair values to mail content while building it (ex: "To:", "address@mail.com")

Property definitions

curl $ CurlMail :: add_pair_to_content
	# Helper method to add pair values to mail content while building it (ex: "To:", "address@mail.com")
	private fun add_pair_to_content(str: String, att: String, val: nullable String): String
	do
		if val != null then return "{str}{att}{val}\n"
		return "{str}{att}\n"
	end
lib/curl/curl.nit:398,2--403,4