addFilter - Add a filter to this query.

            @param filterMethod  <str> - The filter method to use (AND or OR), default: 'AND'
            @param additional args - Filter arguments. @see QueryableListBase.filter

            @raises ValueError if filterMethod is not one of known methods.

def addFilter(self, filterMethod=FILTER_METHOD_AND, **kwargs):
        '''
            addFilter - Add a filter to this query.

            @param filterMethod  <str> - The filter method to use (AND or OR), default: 'AND'
            @param additional args - Filter arguments. @see QueryableListBase.filter

            @raises ValueError if filterMethod is not one of known methods.

        '''
        filterMethod = filterMethod.upper()
        if filterMethod not in FILTER_METHODS:
            raise ValueError('Unknown filter method, %s. Must be one of: %s' %(str(filterMethod), repr(FILTER_METHODS)))

        self.filters.append((filterMethod, kwargs))