Create new Row in Data Frame with ID and date if ID and date do not exist in "x" timeframe

Question

I am trying to add the rows on the second elif statement to the existing dataframe called dfTest. For some reason I get:

local variable 'dfTest' referenced before assignment.

What would be the correct way to achieve this?

The objective is to add a row with x values to dfTest columns if it does not exist a day prior.

  d = {
    'itemID':[2,2,2,2,2,2], 
    'orderedDate':[pd.to_datetime('12/1/21'), pd.to_datetime('12/2/21'), pd.to_datetime('12/3/21'), pd.to_datetime('12/4/21'), pd.to_datetime('12/6/21'), pd.to_datetime('12/7/21')],
    'qty':[1,4,1,1,2,2]
    }

dfTest = pd.DataFrame(d)

def addRowIfNotAdayBefore(row):

  startDate = pd.to_datetime('12/1/21')
  
  rowMinusOneDay = row['orderedDate'] - pd.Timedelta(days=1)

  itemSeries = dfTest.loc[dfTest['itemID'] == row['itemID']]

  exists = itemSeries['orderedDate'] == rowMinusOneDay

  data = [0, 0, 0]

  if row['orderedDate'] == startDate:
    print('This is the first row!')
  elif exists.any():
    print('1st elif')
  elif exists.any() == False:
    print('2nd elif')
    row = {'itemID': row['itemID'], 'orderedDate': rowMinusOneDay, 'qty': 0}
    print(dfNewRows)
    return dfNewRows
    
dfTest.apply(addRowIfNotAdayBefore, axis=1)

dfTest

Current output of dfTest:

itemID	orderedDate	qty
2	12/1/21	1
2	12/2/21	4
2	12/3/21	1
2	12/4/21	1
2	12/5/21	2
2	12/6/21	2

Output of dfTest should be like this:

itemID	orderedDate	qty
2	12/1/21	1
2	12/2/21	4
2	12/3/21	1
2	12/4/21	1
2	12/5/21	0
2	12/6/21	2
2	12/7/21	2