class_docstr: Pattern for a mutable list-like object shareable via a shared
  memory block.  It differs from the built-in list type in that these
  lists can not change their overall length (i.e. no append, insert,
  etc.)
  
  Because values are packed into a memoryview as bytes, the struct
  packing format for any storable value must require no more than 8
  characters to describe its format.
docstr: Gets the back transformation function for a single value.
code: def _get_back_transform(self, position):
      "Gets the back transformation function for a single value."
  
      if (position >= self._list_len) or (self._list_len < 0):
          raise IndexError("Requested position out of range.")
  
      transform_code = struct.unpack_from(
          "b",
          self.shm.buf,
          self._offset_back_transform_codes + position,
      )[0]
      transform_function = self._back_transforms_mapping[transform_code]
  
      return transform_function
  
imports: from functools import partial
  import mmap
  import os
  import errno
  import struct
  import secrets
  import types
label_desc: Use image node_id 4 for calling the ShareableList obj's underlying member method code with example usage: obj._get_back_transform(position) and returns: transform_function