returns the values of all attributes for which the closure returns true. The fact that the values are
returned as a list of Convertible enables conversion. The following formula sums all attributes
whose names are not equal to 'TOTAL':
= attributes.findValues{key, val -> key != 'TOTAL'}.sum(0){it.num0}
Parameters:
closure - A closure that accepts two arguments (String key, Object value) and returns boolean/Boolean.
Returns:
the values of all attributes for which the closure returns true.