# pydicom.datadict.add_dict_entry

`pydicom.datadict.``add_dict_entry`(tag, VR, keyword, description, VM='1', is_retired='')

  Update the DICOM dictionary with a new non-private entry.

  Parameters:

  - tag (int) – The tag number for the new dictionary entry.
  - VR (str) – DICOM value representation.
  - description (str) – The descriptive name used in printing the entry. Often the same as the keyword, but with spaces between words.
  - VM (str, optional) – DICOM value multiplicity. If not specified, then `'1'` is used.
  - is_retired (str, optional) – Usually leave as blank string (default). Set to `'Retired'` if is a retired data element.

  Raises: | `ValueError` – If the tag is a private tag.

  Notes

  Does not permanently update the dictionary, but only during run-time. Will replace an existing entry if the tag already exists in the dictionary.

  See also

  `pydicom.examples.add_dict_entry()`
    Example file which shows how to use this function
  `add_dict_entries()`
    Update multiple values at once.

  Examples

      >>> from pydicom import Dataset
      >>> add_dict_entry(0x10021001, "UL", "TestOne", "Test One")
      >>> add_dict_entry(0x10021002, "DS", "TestTwo", "Test Two", VM='3')
      >>> ds = Dataset()
      >>> ds.TestOne = 'test'
      >>> ds.TestTwo = ['1', '2', '3']