code: def __init__(self, scale, factor, mode):
      self.index = 0
      self.scale = scale
      if factor is None:
          self._log_factor = None
      else:
          if factor < 1.0:
              raise ValueError("'factor' must be >= 1.0")
          self._log_factor = np.log(factor)
  
      if mode not in self.allowed_modes:
          raise ValueError(
              (
                  "'{0}' is not a recognized mode. "
                  "Please select from: {1}"
              ).format(mode, self.allowed_modes)
          )
      self.mode = mode
  
file_path: emcee/src/emcee/moves/gaussian.py
imports: import numpy
  from .mh import MHMove
label_desc: Use image node_id 1 to create a new _isotropic_proposal object from inherited base classes: object with example: obj = _isotropic_proposal(scale, factor, mode)