Move segment_index check

Author: alejoe91

src/spikeinterface/widgets/traces.py

@@ -126,6 +126,11 @@ def __init__(
         else:
             channel_locations = None
 
+        if segment_index is None:
+            if rec0.get_num_segments() != 1:
+                raise ValueError('You must provide "segment_index" for multisegment recordings.')
+            segment_index = 0
+
         if not rec0.has_time_vector(segment_index=segment_index):
             times = None
         else:
@@ -135,11 +140,6 @@ def __init__(
 
         layer_keys = list(recordings.keys())
 
-        if segment_index is None:
-            if rec0.get_num_segments() != 1:
-                raise ValueError('You must provide "segment_index" for multisegment recordings.')
-            segment_index = 0
-
         fs = rec0.get_sampling_frequency()
         if time_range is None:
             time_range = (t_start, t_start + 1.0)