class_docstr: Scale channel types using constant values.
code: def __init__(self, info, scalings, do_scaling=True):
      self._scalings = scalings
      self._info = info
      self._do_scaling = do_scaling
  
imports: import numpy
  from .._fiff.pick import _pick_data_channels, _picks_by_type, _picks_to_idx, pick_info, pick_types
  from ..cov import _check_scalings_user
  from ..filter import filter_data
  from ..time_frequency import psd_array_multitaper
  from ..utils import _check_option, _validate_type, fill_doc, verbose
  from .base import BaseEstimator
  from .mixin import TransformerMixin
label_desc: Use image node_id 1 to create a new _ConstantScaler object  with example: obj = _ConstantScaler(info, scalings, do_scaling)