Getting List of edited Cells after DM load in Planning

Hi - we are loading data from Data management using flat file. There is a Business rule attached to the integration to run after the rule. How can we get the list of edited cells in it so that it can be passed to the FIX statement in the Business Rules. The rule has a line which is as below:

operation.dataValueProvider.dataValueIterator(MemberNameType.ESSBASE_NAME).each {

…

}

My understanding was that it should give the list of edited cells (which can give me list of members) which can be passed to the fix statement. However the rule breaks at this line saying that Method does not exist. I will really appreciate if somebody can guide on this or if there is a workaround this issue.