Python Error unsupported operand type s for int and NoneType

Question

I don t understand this error OR what it means  I will paste my code underneath  but I don t think it is really relevant  I just want to understand this error    It s just a bit of code to add up the letters in all numbers 1 - 1000  inclusive   def number translator x       if x    1          return 3     elif x    2          return 3     elif x    3          return 5     elif x    4          return 4     elif x    5          return 4     elif x    6          return 3     elif x    7          return 5     elif x    8          return 5     elif x    9          return 4     elif x    10          return 3     elif x    11          return 6     elif x    12          return 6     elif x    14          return 8     elif x    15          return 7     elif x    16          return 7     elif x    17          return 9     elif x    18          return 8     elif x    19          return 8     elif x    20          return 6     elif x    30          return 6     elif x    40          return 5     elif x    50          return 5     elif x    60          return 5     elif x    70          return 7     elif x    80          return 6     elif x    90          return 6  count   0 for element in range 1  1001       if element  lt  21          count    number translator element                 for numbers 1 - 20     elif 20  lt  element  lt  100          count    number translator int str element  0     10    number translator int str element  1       for numbers 21 through 100     elif element   100    0 and element    1000          count    number translator int str element  0      7     for numbers divisible by 100  but not 1000     elif element    1000          count    11                                            just for 1000     elif element   100  lt  20          count    number translator int str element  0      10   number translator int str element  1 3           now I add in numbers like 101 - 120  201 - 220  etc      else          count    number translator int str element  0      10   number translator int str element  1     10    number translator int str element  2      now the rest  121  122  123  225  256  984  etc    print count

User · Accepted Answer

When none of the if test in number translator   evaluate to true  the function returns None  The error message is the consequence of that   Whenever you see an error that include  NoneType  that means that you have an operand or an object that is None when you were expecting something else

User · Answer

I got a similar error with     operand while processing images  I discovered the folder included a text file created by the  XnView  image viewer  So  this kind of error occurs when some object is not the kind of object expected

User · Answer

In your giant elif chain  you skipped 13  You might want to throw an error if you hit the end of the chain without returning anything  to catch numbers you missed and incorrect calls of the function       elif x    90      return 6 else      raise ValueError x

[python] Python Error: unsupported operand type(s) for +: 'int' and 'NoneType'

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