SPARQL Query error in python (First example) - python-2.7

Question

import rdflib
g = rdflib.Graph()
g.load("chck.rdf")
for row in g.query(
'select ?s where { [] foaf:knows ?s .}'):
print(row.s)
Note:- chck.rdf was in the same directory
The error is:-
Traceback (most recent call last): File "C:/Python27/exmpl/four.py",
line 6, in
g.load("chck.rdf")
File "C:\Python27\lib\site-packages\rdflib\graph.py", line 1046, in
load
self.parse(source, publicID, format)
File "C:\Python27\lib\site-packages\rdflib\graph.py", line 1039, in
parse
parser.parse(source, self, **args)
File
"C:\Python27\lib\site-packages\rdflib\plugins\parsers\rdfxml.py", line
577, in parse
self._parser.parse(source)
File "C:\Python27\lib\xml\sax\expatreader.py", line 110, in parse
xmlreader.IncrementalParser.parse(self, source)
File "C:\Python27\lib\xml\sax\xmlreader.py", line 123, in parse
self.feed(buffer)
File "C:\Python27\lib\xml\sax\expatreader.py", line 217, in feed
self._err_handler.fatalError(exc)
File "C:\Python27\lib\xml\sax\handler.py", line 38, in fatalError
raise exception
SAXParseException: file:///C:/Python27/exmpl/chck.rdf:132:19: not
well-formed (invalid token)