Look up function:
object
method declaration : (string * string) list
method display_prefix_of_normprefix : string -> string
method display_prefix_of_uri : string -> string
method effective_declaration : (string * string) list
method namespace_manager : Pxp_dtd.namespace_manager
method normprefix_of_display_prefix : string -> string
method parent_scope : Pxp_dtd.namespace_scope option
method uri_of_display_prefix : string -> string
end
