How could I force the "close date" to be mandatory when the "delivery stage" is equal to Closed, Customer Quit or Failed at the opportunity level?

Field Names:
Close Date: CloseDate
Customer Quit
Closed
Failed
Delivery Stage (picklist) FN: Delivery_Stage  API: Delivery_Stage__c

What I have so far:

AND(ispickval(Delivery_Stage__c,"Closed"), ispickval(Delivery_Stage__c,"Customer Quit"), ispickval(Delivery_Stage__c,"Failed"), (CloseDate =""))

Error: Incorrect parameter type for operator '='. Expected Date, received Text

How could I force the "close date" to be mandatory when the "delivery stage" is equal to Closed, Customer Quit or Failed at the opportunity level?

Field Names:
Close Date: CloseDate
Customer Quit
Closed
Failed
Delivery Stage (picklist) FN: Delivery_Stage  API: Delivery_Stage__c

What I have so far:

AND(ispickval(Delivery_Stage__c,"Closed"), ispickval(Delivery_Stage__c,"Customer Quit"), ispickval(Delivery_Stage__c,"Failed"), (CloseDate =""))

Error: Incorrect parameter type for operator '='. Expected Date, received Text