make both external and local files import correctly

src/graphdb.py

@@ -134,13 +134,17 @@ def add_vocabulary(graph: TextIO, graph_name: str, extension: str) -> None:
  """
  print(f"Adding vocabulary {graph_name}")
  content = graph.read()
+ try:
+ content = content.encode('utf-8')
+ except (UnicodeDecodeError, AttributeError):
+ pass
 
  headers = {
  'Content-Type': get_type(extension),
  }
  response = requests.put(
  f"{endpoint}/statements",
- data=content.encode('utf-8'),
+ data=content,
  headers=headers,
  auth=(admin_username, admin_password),
  params={'context': f"<{graph_name}>"},