class_docstr: Stores data in-memory. It's ephemeral and cannot be saved to disk.
docstr: Returns the number of how many documents are present in the DocumentStore.
docstr_tok: ["Returns","the","number","of","how","many","documents","are","present","in","the","DocumentStore","."]
code: def count_documents(self) -> int:
      """
      Returns the number of how many documents are present in the DocumentStore.
      """
      return len(self.storage.keys())
  
imports: import re
  from typing import Literal, Any, Dict, List, Optional, Iterable
  import logging
  import numpy
  from haystack_bm25 import rank_bm25
  from tqdm.auto import tqdm
  from haystack import default_from_dict, default_to_dict
  from haystack.dataclasses import Document
  from haystack.document_stores.types import DuplicatePolicy
  from haystack.utils.filters import document_matches_filter, convert
  from haystack.document_stores.errors import DuplicateDocumentError, DocumentStoreError
  from haystack.utils import expit
label_desc: Use image node_id 4 for calling the InMemoryDocumentStore obj's underlying member method code with example usage: obj.count_documents() and returns: len