def calc_seasonality(freq):
   match freq:
     case 'Y':
       return 10
     case 'Q':
       return 4
     case 'M':
       return 12
     case 'W':
       return 4
     case 'D':
       return 7
     case _:
       return "You didn't choose the correct frequency. Use: Y, Q, M, W and D"