fix docstr and whats_new

docs/whats_new.rst

@@ -32,7 +32,7 @@ Current
 
 Changelog
 ~~~~~~~~~
-- It's now possible to pass kwargs arguments to the notch filter inside prep; see the ``filter_kwargs`` parameter by `Yorguin Mantilla`_ (`#40 <https://github.com/sappelhoff/pyprep/pull/40>`_)
+- It's now possible to pass keyword arguments to the notch filter inside prep; see the ``filter_kwargs`` parameter by `Yorguin Mantilla`_ (`#40 <https://github.com/sappelhoff/pyprep/pull/40>`_)
 - The default filter length for the spectrum_fit method will be '10s' to fix memory issues, by `Yorguin Mantilla`_ (`#40 <https://github.com/sappelhoff/pyprep/pull/40>`_)
 - Channel types  are now available from a new ``ch_types_all`` attribute, and non-EEG channel names are now available from a new ``ch_names_non_eeg`` attribute from :class:`pyprep.PrepPipeline`, by `Yorguin Mantilla`_ (`#34 <https://github.com/sappelhoff/pyprep/pull/34>`_)
 - Renaming of ``ch_names`` attribute of ``PrepPipeline`` to ``ch_names_all``, by `Yorguin Mantilla`_ (`#34 <https://github.com/sappelhoff/pyprep/pull/34>`_)

pyprep/prep_pipeline.py

@@ -40,9 +40,12 @@ class PrepPipeline:
         an int, it will be used as a seed for RandomState.
         If None, the seed will be obtained from the operating system
         (see RandomState for details). Default is None.
-    filter_kwargs : dictionary
-        Keywords arguments for the mne.filter.notch_filter function.
-        Note Fs and freqs are already set up by the prep_params dictionary.
+    filter_kwargs : dict | None
+        Optional keywords arguments to be passed on to mne.filter.notch_filter.
+        Do not set the "x", Fs", and "freqs" arguments via the filter_kwargs
+        parameter, but use the "raw" and "prep_params" parameters instead.
+        If None is passed, the pyprep default settings for filtering are used
+        instead.
 
     Attributes
     ----------