setStrategy_options syntax in thrift

[A J]

What is the syntax of setStrategy_options in thrift.

The following fails:

Util.java:22: 
setStrategy_options(java.util.Map<java.lang.String,java.lang.String>)
in org.apache.cassandra.thrift.KsDef cannot be applied to
(java.lang.String)
        newKs.setStrategy_options("{replication_factor:2}");