A comma after a value turns it into tuple. Probably not what you intended to do.

As far as the Python parser is concerned the parentheses are optional for non-empty tuples. According to the documentation: it is actually the comma which makes a tuple, not the parentheses. The parentheses are optional, except in the empty tuple case.

value = (1)  # evaluates to int
value = 1,  # evaluates to tuple with one element
value = (1,)  # evaluates to tuple with one element
value = 1, 2  # evaluates to tuple with two elements

By accidentally suffixing a comma on value = 1, expect to get a TypeError when the code later attempts to perform integer operations on a variable that evaluated to tuple.