def _get_meg_system(info):
 system = '306m'
 for ch in info['chs']:
  if (ch['kind'] == FIFF.FIFFV_MEG_CH):
   coil_type = (ch['coil_type'] & 65535)
   if (coil_type == FIFF.FIFFV_COIL_NM_122):
    system = '122m'
    break
   elif ((coil_type // 1000) == 3):
    system = '306m'
    break
   elif ((coil_type == FIFF.FIFFV_COIL_MAGNES_MAG) or (coil_type == FIFF.FIFFV_COIL_MAGNES_GRAD)):
    nmag = np.sum([(c['kind'] == FIFF.FIFFV_MEG_CH) for c in info['chs']])
    system = ('Magnes_3600wh' if (nmag > 150) else 'Magnes_2500wh')
    break
   elif (coil_type == FIFF.FIFFV_COIL_CTF_GRAD):
    system = 'CTF_275'
    break
   elif (coil_type == FIFF.FIFFV_COIL_KIT_GRAD):
    system = 'KIT'
    break
   elif (coil_type == FIFF.FIFFV_COIL_BABY_GRAD):
    system = 'BabySQUID'
    break
 return system

def _get_meg_system ( info ) : system = '306m' for ch in info [ 'chs' ] : if ( ch [ 'kind' ] == FIFF . FIFFV_MEG_CH ) : coil_type = ( ch [ 'coil_type' ] & 65535 ) if ( coil_type == FIFF . FIFFV_COIL_NM_122 ) : system = '122m' break elif ( ( coil_type // 1000 ) == 3 ) : system = '306m' break elif ( ( coil_type == FIFF . FIFFV_COIL_MAGNES_MAG ) or ( coil_type == FIFF . FIFFV_COIL_MAGNES_GRAD ) ) : nmag = np . sum ( [ ( c [ 'kind' ] == FIFF . FIFFV_MEG_CH ) for c in info [ 'chs' ] ] ) system = ( 'Magnes_3600wh' if ( nmag > 150 ) else 'Magnes_2500wh' ) break elif ( coil_type == FIFF . FIFFV_COIL_CTF_GRAD ) : system = 'CTF_275' break elif ( coil_type == FIFF . FIFFV_COIL_KIT_GRAD ) : system = 'KIT' break elif ( coil_type == FIFF . FIFFV_COIL_BABY_GRAD ) : system = 'BabySQUID' break return system
educated guess for the helmet type based on channels .