code: def get_extensions(cls):
          
  
          file_extension_set = set()
          for table_format in TableFormat:
              for file_extension in table_format.file_extensions:
                  file_extension_set.add(file_extension)
  
          return sorted(list(file_extension_set))
docs: :return: Available file extensions.
          :rtype: list
  
          :Example:
              .. code:: python
  
                  >>> import pytablewriter as ptw
                  >>> for name in ptw.TableWriterFactory.get_extensions():
                  ...     print(name)
                  ...
                  csv
                  htm
                  html
                  js
                  json
                  jsonl
                  ldjson
                  ltsv
                  md
                  ndjson
                  py
                  rst
                  sqlite
                  sqlite3
                  tex
                  toml
                  tsv
                  xls
                  xlsx