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.count(value) -> integer -- return number of occurrences of value.
code: def count(self, value):
      "L.count(value) -> integer -- return number of occurrences of value."
  
      return sum(value == entry for entry in self)
  
imports: from functools import partial
  import mmap
  import os
  import errno
  import struct
  import secrets
  import types
label_desc: Use image node_id 18 for calling the ShareableList obj's underlying member method code with example usage: obj.count(value) and returns: sum