If @is_a_type is a derivable type, check whether @type is a descendant of @is_a_type. If @is_a_type is an interface, check whether @type conforms to it.
type to check anchestry for
possible anchestor of @type or interface that @type could conform to
%TRUE if @type is a @is_a_type
See Implementation
If @is_a_type is a derivable type, check whether @type is a descendant of @is_a_type. If @is_a_type is an interface, check whether @type conforms to it.