class_docstr: Base class for defining arms.
  
  Randomization in experiments assigns units to a given arm. Thus, the arm
  encapsulates the parametrization needed by the unit.
code: def name(self, name: str) -> None:
      if self._name is not None:
          raise ValueError("Arm name is not mutable once set.")
      self._name = name
  
imports: import hashlib
  import json
  from typing import Optional
  from ax.core.types import TParameterization
  from ax.utils.common.base import SortableBase
  from ax.utils.common.equality import equality_typechecker
  from ax.utils.common.typeutils import numpy_type_to_python_type
label_desc: Use image node_id 6 for calling the Arm obj's underlying member method code with example usage: obj.name(name) without return types