Fix the 'cannot assign to struct field in map' error by retrieving the struct, modifying it, and reassigning it to the map key.
You cannot modify a struct field directly because the struct value inside the map is a copy, not an addressable variable. Retrieve the struct, modify it, and assign it back to the map.
m := map[string]MyStruct{"key": {}}
m["key"].Field = 10 // Error: cannot assign to struct field in map
// Fix: Retrieve, modify, reassign
s := m["key"]
s.Field = 10
m["key"] = s
Go maps store copies of their values, so you cannot change a part of a value directly inside the map. You must take the value out, change it, and put it back. It's like trying to fix a car part while it's still in the engine; you have to remove the part, fix it, and reinstall it.