[FIXED] ValueError: dictionary update sequence element #0 has length 1; 2 is required in Python3.10

Issue

Something went wrong with python3.10, no warning or any notice in the Pycharm validation. It just recommended the space by following the PEP 8: E231 missing white space after ':'

class Margin:
    def __init__(self):
        self.__margin = {}

    def setMargin(self, value: dict= None) -> None:
        self.__margin.update(value or {'all': '', 'android': {}, 'ios': {}})

Calling the method without a parameter

obj = Margin()
obj.setMargin()

Then everything was fine with adding space, but on the run time, it showed me the error.

 File "/var/www/avb/n.py", line 1195, in setMargin
    self.__margin.update(value or {'all': '', 'android': {}, 'ios': {}})
ValueError: dictionary update sequence element #0 has length 1; 2 is required

Solution

You get this error generally,

when you try to update a dictionary like this:

d = {}

d.update([(100,)])

#or

d.update([[1]])

#output

ValueError: dictionary update sequence element #0 has length 1; 2 is required

You also get this error when you have dictionary inside a string like this:

d = '{"a":1,"b":2}'

then you try to convert it into a dictionary by:

dict(d)

#output

ValueError: dictionary update sequence element #0 has length 1; 2 is required

You have to check how you have defined your class and how the object obj is created.

Answered By - Goku - stands with Palestine