'Check channel type membership.
Parameters
ch_type : str
Channel type to check for. Can be e.g. \'meg\', \'eeg\', \'stim\', etc.
Returns
in : bool
Whether or not the instance contains the given channel type.
Examples
Channel type membership can be tested as::
>>> \'meg\' in inst  # doctest: +SKIP
True
>>> \'seeg\' in inst  # doctest: +SKIP
False'

def __contains__(self, ch_type):

    if (ch_type == 'meg'):
        has_ch_type = (_contains_ch_type(self.info, 'mag') or _contains_ch_type(self.info, 'grad'))
    else:
        has_ch_type = _contains_ch_type(self.info, ch_type)
    return has_ch_type
