how can i run RandomRowFilter in happybase

I want to sample rowkey in hbase by happybase(because of memory limit) So I search and implemet

import happybase

"""~ """"
table = connection.table('drivers')
a=list(table.scan(filter="RandomRowFilter (chance=0.1f)" ))
or a=list(table.scan(filter="RandomRowFilter ('chance',=,'0.1')" ))
print a

but it always say thrift.Thrift.TApplicationException: Internal error processing scannerOpenWithScan

is there any example code for RandomRowFilter example in python?

version check is all right because of [thrift hbase client - support filters and coprocessors I ran this code...

Please help me