Yahoo! JAPAN

2013/8/1 -If a local does not have a definition before an assignment, the Python interpreter does not know what to do, so it throws this error. The ...

2023/1/24 -The rule is that if you assign to a name in a function, the name is assumed to be local to that function unless you say otherwise with ...

2026/10/1 -UnboundLocalError occurs when Python tries to access a local variable before that variable has been assigned a value.

2023/9/27 -One way to fix this error is to initialize the variable before using it. This ensures that the variable exists in the local scope before it is ...

2020/10/8 -The Unboundlocalerror: local variable referenced before assignment is raised when you try to use a variable before it has been assigned in the ...

2026/7/3 -The exception UnboundLocalError: local variable 'index' referenced before assignment happens in Python when you use a global variable in a ...

2020/8/10 -On Career Karma, learn about the Python local variable referenced before assignment error, how the error works, and how to solve the error.

2025/7/23 -This error occurs when a local variable is referenced before it has been assigned a value within a function or method. This error typically ...

Looks like it is becasue you cannot modify a global variable (on_off) inside a function without declaring it as global. That may be the solution but the cause ...