float() argument must be a string or a number, not 'method'

This error message is raised when you try to pass a method (a function that belongs to a class) as an argument to the `float()` function in Python. The `float()` function is used to convert a string or a number to a floating point number.

For example, let's say you have a method `my_method()` in a class `MyClass`:

class MyClass:
    def my_method(self):
        return 10.5

And you try to pass this method as an argument to the `float()` function:

obj = MyClass()
result = float(obj.my_method)

This will raise the error message:

TypeError: float() argument must be a string or a number, not 'method'

To fix this error, you need to call the method and pass the result to the `float()` function:

obj = MyClass()
result = float(obj.my_method())

Now, `result` will be a floating point number.