About: http://webisa.webdatacommons.org/153587245

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Otherwise, sub_foo gets defined in the namespace that is active the first time it is required, and the next require is a no-op because that file is already in %INC. The same problem can happen with global variables.
http://www.w3.org/ns/prov#wasQuotedFrom	cpan.org