Balances.deleteNestedBalance() deletes Balances.BalancesStruct which contains a mapping:
	-delete nestedStackBalance

Balances.deleteBalance(uint256) deletes Balances.BalancesStruct which contains a mapping:
	-delete stackBalance[idx]

Lib.deleteSt(Lib.MyStruct[1]) deletes Lib.MyStruct which contains a mapping:
	-delete st[0]

