1 files changed, 2 insertions, 1 deletions
diff --git a/synapse/config/__main__.py b/synapse/config/__main__.py
index c555f5f914..b2a7a89a35 100644
--- a/synapse/config/__main__.py
+++ b/synapse/config/__main__.py
@@ -13,12 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import sys
+from typing import List
 
 from synapse.config._base import ConfigError
 from synapse.config.homeserver import HomeServerConfig
 
 
-def main(args):
+def main(args: List[str]) -> None:
     action = args[1] if len(args) > 1 and args[1] == "read" else None
     # If we're reading a key in the config file, then `args[1]` will be `read`  and `args[2]`
     # will be the key to read.