There is a problem with removing all whitespaces - This doesn't work: 

`picks = mne.fiff.pick_channels(raw.ch_names,'MEG2331')` 
but this does 
`picks = mne.fiff.pick_channels(raw.ch_names,'MEG 2331')`. 

The other alternative is to remove the whitespace after the comma, but how many spaces? Will `replace(', ',',')` work when there are more than one spaces after the comma, I guess not?