Refactor qry_sum methods to extend columns before querying and improve readability

eispajak/models/payment.py

@@ -82,10 +82,12 @@ class PaymentPBB(PCBase, DefaultModel):
 
     @classmethod
     def qry_sum(cls, columns=[]):
-        qry = PCDBSession.query(
+        columns.extend(
             func.sum(cls.jml_sppt_yg_dibayar).label('bayar'),
             func.sum(cls.denda_sppt).label('denda'),
-            func.count(cls.id).label('trx')).select_from(cls)
+            func.count(cls.id).label('trx')
+        )
+        qry = PCDBSession.query().select_from(cls)
         for col in columns:
             qry=qry.add_columns(col)
         return qry
@@ -123,10 +125,13 @@ class PaymentBPHTB(PCBase, models.CommonModel):
 
     @classmethod
     def qry_sum(cls, columns=[]):
-        qry = PCDBSession.query(
+        columns.extend([
             func.sum(cls.nilai_bphtb).label('bayar'),
             literal_column("0").label('denda'),
-            func.count(cls.id).label('trx')).select_from(cls)
+            func.count(cls.id).label('trx')]
+        )
+
+        qry = PCDBSession.query().select_from(cls)
         for col in columns:
             qry = qry.add_columns(col)
         return qry
@@ -178,10 +183,10 @@ class PaymentPAD(PCBase, models.CommonModel):
 
     @classmethod
     def qry_sum(cls, columns=[]):
-        qry = PCDBSession.query(
-            func.sum(cls.jml_bayar).label('bayar'),
+        columns.extend([func.sum(cls.jml_bayar).label('bayar'),
                        func.sum(cls.denda+cls.bunga).label('denda'),
-            func.count(cls.id).label('trx')).select_from(cls)
+                       func.count(cls.id).label('trx')])
+        qry = PCDBSession.query().select_from(cls)
         for col in columns:
             qry = qry.add_columns(col)
         return qry
@@ -219,10 +224,12 @@ class PaymentWEBR(PCBase, models.CommonModel):
 
     @classmethod
     def qry_sum(cls, columns=[]):
-        qry = PCDBSession.query(
+        columns.extend([
             func.sum(cls.jml_bayar).label('bayar'),
             func.sum(cls.denda).label('denda'),
-            func.count(cls.id).label('trx')).select_from(cls)
+            func.count(cls.id).label('trx')
+        ])
+        qry = PCDBSession.query().select_from(cls)
         for col in columns:
             qry = qry.add_columns(col)
         return qry