class
	PROXY_INFORMATION

General
	cluster: transfer
	description: "Information about proxies"
	create: make

Ancestors
	HOST_VALIDITY_CHECKER

Queries
	host: STRING_8
	port: INTEGER_32
	proxy_host_ok (h: STRING_8): BOOLEAN

Commands
	set_host (h: STRING_8)
	set_port (p: INTEGER_32)

Constraints
	host not empty
	host valid
	port non negative