contained_combined_ranges: fix type annotation.

This function requires as input a Sequence of signal names, not merely
a Collection.

(There's no particular reason this function *couldn't* be written to
accept any Collection or even any Iterable, but at present it requires
the argument to be something that implements both __len__ and
__getitem__.)

Author: Benjamin Moody

wfdb/io/_header.py

@@ -1,5 +1,5 @@
 import datetime
-from typing import Collection, List, Tuple
+from typing import List, Sequence, Tuple
 
 import numpy as np
 import pandas as pd
@@ -920,7 +920,7 @@ def contained_ranges(self, sig_name: str) -> List[Tuple[int, int]]:
 
     def contained_combined_ranges(
         self,
-        sig_names: Collection[str],
+        sig_names: Sequence[str],
     ) -> List[Tuple[int, int]]:
         """
         Given a collection of signal name, return the sample ranges that