class_docstr: Manage and provide access to all of the models that belong to a Bokeh
  Document.
  
  The set of "all models" means specifically all the models reachable from
  references form a Document's roots.
class_docstr_tok: ["Manage","and","provide","access","to","all","of","the","models","that","belong","to","a","Bokeh","Document",".","The","set","of","``","all","models","''","means","specifically","all","the","models","reachable","from","references","form","a","Document","'s","roots","."]
docstr: Find the model for this Document with a given ID.
  
  Args:
      id (ID) : model ID to search for
          If no model with the given ID exists, returns None
  
  Return:
      a Model or None
docstr_tok: ["Find","the","model","for","this","Document","with","a","given","ID",".","Args",":","id","(","ID",")",":","model","ID","to","search","for","If","no","model","with","the","given","ID","exists",",","returns","None","Return",":","a","Model","or","None"]
code: def get_by_id(self, id: ID) -> Model | None:
      """Find the model for this Document with a given ID.
  
      Args:
          id (ID) : model ID to search for
              If no model with the given ID exists, returns None
  
      Return:
          a Model or None
  
      """
      return self._models.get(id, None)
  
imports: from __future__ import annotations
  import logging
  import contextlib
  import weakref
  from typing import TYPE_CHECKING, Callable, Generator, Iterator
  from ..core.types import ID
  from ..model import Model
  from ..util.datatypes import MultiValuedDict
label_desc: Use image node_id 10 for calling the DocumentModelManager obj's underlying member method code with example usage: obj.get_by_id(id) and returns: self