Change the way connection modes are specified

telethon/_misc/enums.py

@@ -0,0 +1,22 @@
+from enum import Enum
+
+
+class ConnectionMode(Enum):
+    FULL = 'full'
+    INTERMEDIATE = 'intermediate'
+    ABRIDGED = 'abridged'
+    OBFUSCATED = 'obfuscated'
+    HTTP = 'http'
+
+
+def parse_conn_mode(mode):
+    if isinstance(mode, ConnectionMode):
+        return mode
+    elif isinstance(mode, str):
+        for cm in ConnectionMode:
+            if mode == cm.value:
+                return cm
+
+        raise ValueError(f'unknown connection mode: {mode!r}')
+    else:
+        raise TypeError(f'not a valid connection mode: {type(mode).__name__!r}')