def setFormula(self, Formula=None):
        """Set the Dependent Services from the text of the calculation Formula
        """
        bsc = getToolByName(self, 'bika_setup_catalog')
        if Formula is None:
            self.setDependentServices(None)
            self.getField('Formula').set(self, Formula)
        else:
            keywords = re.compile(r"\[([^.^\]]+)\]").findall(Formula)
            brains = bsc(portal_type='AnalysisService',
                         getKeyword=keywords)
            services = [brain.getObject() for brain in brains]
            self.getField('DependentServices').set(self, services)
            self.getField('Formula').set(self, Formula)
Set the Dependent Services from the text of the calculation Formula