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 a single model for this Document with a given name.
  
  If multiple models are found with the name, an error is raised.
  
  Args:
      name (str) : the name of a model to search for
  
  Returns
      A model with the given name, or None
docstr_tok: ["Find","a","single","model","for","this","Document","with","a","given","name",".","If","multiple","models","are","found","with","the","name",",","an","error","is","raised",".","Args",":","name","(","str",")",":","the","name","of","a","model","to","search","for","Returns","A","model","with","the","given","name",",","or","None"]
code: def get_one_by_name(self, name: str) -> Model | None:
      """Find a single model for this Document with a given name.
  
      If multiple models are found with the name, an error is raised.
  
      Args:
          name (str) : the name of a model to search for
  
      Returns
          A model with the given name, or None
  
      """
      return self._models_by_name.get_one(
          name, f"Found more than one model named '{name}'"
      )
  
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 11 for calling the DocumentModelManager obj's underlying member method code with example usage: obj.get_one_by_name(name) and returns: self