update function call

cx1111 · cx1111 · commit f53dacb6436d · 2018-07-17T15:03:15.000-04:00
diff --git a/wfdb/io/_header.py b/wfdb/io/_header.py
@@ -377,7 +377,7 @@ def set_default(self, field):
 
             # Set more specific defaults if possible
             if field == 'adc_res' and self.fmt is not None:
-                self.adc_res = _signal.fmt_res(self.fmt)
+                self.adc_res = _signal._fmt_res(self.fmt)
                 return
 
             setattr(self, field,
