Add return type Document for parse_file

Signed-off-by: Arthit Suriyawongkul <arthit@gmail.com>

src/spdx_tools/spdx/parser/parse_anything.py

@@ -12,14 +12,15 @@
 import logging
 
 from spdx_tools.spdx.formats import FileFormat, file_name_to_format
+from spdx_tools.spdx.model import Document
 from spdx_tools.spdx.parser.json import json_parser
 from spdx_tools.spdx.parser.rdf import rdf_parser
 from spdx_tools.spdx.parser.tagvalue import tagvalue_parser
 from spdx_tools.spdx.parser.xml import xml_parser
 from spdx_tools.spdx.parser.yaml import yaml_parser
 
 
-def parse_file(file_name: str, encoding: str = "utf-8"):
+def parse_file(file_name: str, encoding: str = "utf-8") -> Document:
     if encoding != "utf-8":
         logging.warning(
             "It's recommended to use the UTF-8 encoding for any SPDX file. Consider changing the encoding of the file."