About: http://webisa.webdatacommons.org/428040735

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	Irrespective of your subject line, it looks like you really want to check if d is a data frame or something else.
http://www.w3.org/ns/prov#wasQuotedFrom	stackoverflow.com