CEEMDAN.ceemdan() missing 1 required positional argument: 'S'

This error message means that the method `ceemdan()` of the `CEEMDAN` class is missing a required positional argument 'S'. This argument is necessary for the method to work properly.

To solve this error, you need to provide the missing argument 'S' to the `ceemdan()` method. The argument 'S' is usually the input signal that needs to be decomposed using the CEEMDAN algorithm.

Here's an example code snippet that shows how to use the `ceemdan()` method with an input signal 'x':

from ceemdan import CEEMDAN

# create a CEEMDAN object
ceemdan = CEEMDAN()

# input signal
x = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

# decompose the signal using CEEMDAN
imfs = ceemdan.ceemdan(x, S=None)

In this example, the `ceemdan()` method is called with the input signal 'x' and the argument 'S' is set to None. The 'S' argument is optional and can be used to provide an initial guess for the mode mixing matrix. If 'S' is not provided, the algorithm will use a random matrix as the initial guess.