diff --git a/gen_seq_diag.py b/gen_seq_diag.py
index 6eb1d5c4d6a896c39901d1e81f661298eac93281..4c7a5b451dff568272c05b7009c89ecce6ee0dc1 100755
--- a/gen_seq_diag.py
+++ b/gen_seq_diag.py
@@ -178,7 +178,9 @@ class Call(Stmt):
                 return
 
         # check for recursion
-        id_ = (met2.t.name, met2.name)
+        id_ = None
+        if met2 is not None:
+            id_ = (met2.t.name, met2.name)
         if id_ in ctx.vis:
             ctx.comment(lvl, f'recur {call.qual}.{call.member}')
             return
@@ -211,7 +213,8 @@ class Call(Stmt):
                    f'dt=7' +
                    ']' +
                    f'{{{edge[0]}}}{{{edge[1]}}}')
-        met2.gen_seq(var, lvl + 1, ctx)
+        if met2 is not None:
+            met2.gen_seq(var, lvl + 1, ctx)
         ctx.append(lvl, '\\end{umlcall}')
 
         if call.ret is not None: