docstr: Return the MemoryFile with the given filename. Filenames are of the
  form "file_id.extension". (Note that this is *not* the optional
  user-specified filename for download files.)
  
  Raises a MediaFileStorageError if no such file exists.
docstr_tok: ["Return","the","MemoryFile","with","the","given","filename",".","Filenames","are","of","the","form","``","file_id.extension","''",".","(","Note","that","this","is","*","not","*","the","optional","user-specified","filename","for","download","files",".",")","Raises","a","MediaFileStorageError","if","no","such","file","exists","."]
code: def get_file(self, filename: str) -> MemoryFile:
      """Return the MemoryFile with the given filename. Filenames are of the
      form "file_id.extension". (Note that this is *not* the optional
      user-specified filename for download files.)
  
      Raises a MediaFileStorageError if no such file exists.
      """
      file_id = os.path.splitext(filename)[0]
      try:
          return self._files_by_id[file_id]
      except KeyError as e:
          raise MediaFileStorageError(
              f"Bad filename '{filename}'. (No media file with id '{file_id}')"
          ) from e
  
imports: import contextlib
  import hashlib
  import mimetypes
  import os.path
  from typing import Dict, List, NamedTuple, Optional, Union
  from typing_extensions import Final
  from streamlit.logger import get_logger
  from streamlit.runtime.media_file_storage import MediaFileKind, MediaFileStorage, MediaFileStorageError
  from streamlit.runtime.stats import CacheStat, CacheStatsProvider, group_stats
  from streamlit.util import HASHLIB_KWARGS
label_desc: Use image node_id 3 for calling the MemoryMediaFileStorage obj's underlying member method code with example usage: obj.get_file(filename) and returns: self