AttributeError: ‘NoneType‘ object has no attribute ‘append‘

Python error:
attributeerror: ‘nonetype’ object has no attribute ‘append’

a = a.append(b)

After one execution, the type of a changes to nonetype
the above errors will appear in the next execution.

This is because append modifies a itself and returns none. The return value cannot be reassigned to a.

terms of settlement:

Change the variable name:
C =]
b = [1,2,3,4]
C = A. append (b)
problem solving.

change a = a.append (b) to a.append (b)

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