The fourth block of `AR_identification.ipynb` is shown as follows: ```python # list of all filters (with other values like names, and positions in figures) filters = [ {"name": "LMS", "mu_s": 0.001, "mu_e": 0.05, "filter": pa.filters.FilterLMS(n), "plot_position": 221 }, {"name": "NLMS", "mu_s": 0.01, "mu_e": 2., "filter": pa.filters.FilterNLMS(n), "plot_position": 222 }, {"name": "GNGD", "mu_s": 0.01, "mu_e": 4., "filter": pa.filters.FilterGNGD(n), "plot_position": 223 }, {"name": "RLS", "mu_s": 0.001, "mu_e": 1., "filter": pa.filters.FilterRLS(n), "plot_position": 224 }, ] ``` It seems each "filter"'s initialization is missing a necessary parameter "mu" which is leading to the error in the title.