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: L.index(value) -> integer -- return first index of value.
  Raises ValueError if the value is not present.
code: def index(self, value):
      """L.index(value) -> integer -- return first index of value.
      Raises ValueError if the value is not present."""
  
      for position, entry in enumerate(self):
          if value == entry:
              return position
      else:
          raise ValueError(f"{value!r} not in this container")
  
imports: from functools import partial
  import mmap
  import os
  import errno
  import struct
  import secrets
  import types
  from .None import resource_tracker
label_desc: Use image node_id 19 for calling the ShareableList obj's underlying member method code with example usage: obj.index(value) and returns: position