add return type

src/kyupy/vcd.py

@@ -154,7 +154,7 @@ GRAMMAR = r"""
     """
 
 
-def load(file, var_locs = lambda _: [], step_filter = lambda *_: True, s_len = None):
+def load(file, var_locs = lambda _: [], step_filter = lambda *_: True, s_len = None) -> VcdData:
     """Parses the contents of ``file`` as Verilog Change Dump (VCD).
 
     :param file: A file name or a file handle. Files with `.gz`-suffix are decompressed on-the-fly.