ConditionType not found

Groovy:Apparent variable ‘ConditionType’ was found in a static scope but doesn’t refer to a local variable, static field or class. Possible causes:
this is what i get when I add
static TestObject makeTO(String css)
TestObject to = new TestObject()
to.addProperty(“css”, ConditionType.EQUALS, css)
return to
to my custom keywords

Add this to your imports:

import com.kms.katalon.core.testobject.ConditionType