class_docstr: Raw data in FIF format.
  
  Parameters
  ----------
  fname : path-like | file-like
      The raw filename to load. For files that have automatically been split,
      the split part will be automatically loaded. Filenames not ending with
      ``raw.fif``, ``raw_sss.fif``, ``raw_tsss.fif``, ``_meg.fif``,
      ``_eeg.fif``,  or ``_ieeg.fif`` (with or without an optional additional
      ``.gz`` extension) will generate a warning. If a file-like object is
      provided, preloading must be used.
  
      .. versionchanged:: 0.18
         Support for file-like objects.
  allow_maxshield : bool | str (default False)
      If True, allow loading of data that has been recorded with internal
      active compensation (MaxShield). Data recorded with MaxShield should
      generally not be loaded directly, but should first be processed using
      SSS/tSSS to remove the compensation signals that may also affect brain
      activity. Can also be "yes" to load without eliciting a warning.
  %(preload)s
  %(on_split_missing)s
  %(verbose)s
  
  Attributes
  ----------
  %(info_not_none)s
  ch_names : list of string
      List of channels' names.
  n_times : int
      Total number of time points in the raw file.
  times :  ndarray
      Time vector in seconds. Starts from 0, independently of `first_samp`
      value. Time interval between consecutive time samples is equal to the
      inverse of the sampling frequency.
  preload : bool
      Indicates whether raw data are in memory.
  %(verbose)s
docstr: Fix Elekta magnetometer coil types.
  
  Returns
  -------
  raw : instance of Raw
      The raw object. Operates in place.
  
  Notes
  -----
  This function changes magnetometer coil types 3022 (T1: SQ20483N) and
  3023 (T2: SQ20483-A) to 3024 (T3: SQ20950N) in the channel definition
  records in the info structure.
  
  Neuromag Vectorview systems can contain magnetometers with two
  different coil sizes (3022 and 3023 vs. 3024). The systems
  incorporating coils of type 3024 were introduced last and are used at
  the majority of MEG sites. At some sites with 3024 magnetometers,
  the data files have still defined the magnetometers to be of type
  3022 to ensure compatibility with older versions of Neuromag software.
  In the MNE software as well as in the present version of Neuromag
  software coil type 3024 is fully supported. Therefore, it is now safe
  to upgrade the data files to use the true coil type.
  
  .. note:: The effect of the difference between the coil sizes on the
            current estimates computed by the MNE software is very small.
            Therefore the use of mne_fix_mag_coil_types is not mandatory.
docstr_tok: ["Fix","Elekta","magnetometer","coil","types",".","Returns","--","--","--","-","raw",":","instance","of","Raw","The","raw","object",".","Operates","in","place",".","Notes","--","--","-","This","function","changes","magnetometer","coil","types","3022","(","T1",":","SQ20483N",")","and","3023","(","T2",":","SQ20483-A",")","to","3024","(","T3",":","SQ20950N",")","in","the","channel","definition","records","in","the","info","structure",".","Neuromag","Vectorview","systems","can","contain","magnetometers","with","two","different","coil","sizes","(","3022","and","3023","vs.","3024",")",".","The","systems","incorporating","coils","of","type","3024","were","introduced","last","and","are","used","at","the","majority","of","MEG","sites",".","At","some","sites","with","3024","magnetometers",",","the","data","files","have","still","defined","the","magnetometers","to","be","of","type","3022","to","ensure","compatibility","with","older","versions","of","Neuromag","software",".","In","the","MNE","software","as","well","as","in","the","present","version","of","Neuromag","software","coil","type","3024","is","fully","supported",".","Therefore",",","it","is","now","safe","to","upgrade","the","data","files","to","use","the","true","coil","type",".","..","note",":",":","The","effect","of","the","difference","between","the","coil","sizes","on","the","current","estimates","computed","by","the","MNE","software","is","very","small",".","Therefore","the","use","of","mne_fix_mag_coil_types","is","not","mandatory","."]
code: def fix_mag_coil_types(self):
      """Fix Elekta magnetometer coil types.
  
      Returns
      -------
      raw : instance of Raw
          The raw object. Operates in place.
  
      Notes
      -----
      This function changes magnetometer coil types 3022 (T1: SQ20483N) and
      3023 (T2: SQ20483-A) to 3024 (T3: SQ20950N) in the channel definition
      records in the info structure.
  
      Neuromag Vectorview systems can contain magnetometers with two
      different coil sizes (3022 and 3023 vs. 3024). The systems
      incorporating coils of type 3024 were introduced last and are used at
      the majority of MEG sites. At some sites with 3024 magnetometers,
      the data files have still defined the magnetometers to be of type
      3022 to ensure compatibility with older versions of Neuromag software.
      In the MNE software as well as in the present version of Neuromag
      software coil type 3024 is fully supported. Therefore, it is now safe
      to upgrade the data files to use the true coil type.
  
      .. note:: The effect of the difference between the coil sizes on the
                current estimates computed by the MNE software is very small.
                Therefore the use of mne_fix_mag_coil_types is not mandatory.
      """
      fix_mag_coil_types(self.info)
      return self
  
imports: import copy
  import os
  import os.path
  import numpy
  from ..._fiff.constants import FIFF
  from ..._fiff.meas_info import read_meas_info
  from ..._fiff.open import _fiff_get_fid, _get_next_fname, fiff_open
  from ..._fiff.tag import _call_dict, read_tag
  from ..._fiff.tree import dir_tree_find
  from ..._fiff.utils import _mult_cal_one
  from ...annotations import Annotations, _read_annotations_fif
  from ...channels import fix_mag_coil_types
  from ...event import AcqParserFIF
  from ...utils import _check_fname, _file_like, _on_missing, check_fname, fill_doc, logger, verbose, warn
  from ..base import BaseRaw, _check_maxshield, _check_raw_compatibility, _get_fname_rep, _RawShell
label_desc: Use image node_id 5 for calling the Raw obj's underlying member method code with example usage: obj.fix_mag_coil_types() and returns: self