I have defined properties probability and attr for a relation as below:
:START_ID;role;:END_ID;:TYPE;probability;attr:float
keanu;'Neo';tt0133093;ACTED_IN;0.1;0.1
keanu;'Neo';tt0234215;ACTED_IN;0.2;0.2
keanu;'Neo';tt0242653;ACTED_IN;0.3;0.3
laurence;...
