Revert "Reinsert type check in merge loop."

This reverts commit eeb8053.

Author: alexandermorgan

pvlib/bifacial.py

@@ -182,7 +182,6 @@ def merge(reports):
         report = reports[0]
         keys_report = list(report.keys())
         for other_report in reports[1:]:  # loop won't run if len(reports) < 2
-            if isinstance(other_report, dict):
-                for key in keys_report:
-                    report[key] += other_report[key]
+            for key in keys_report:
+                report[key] += other_report[key]
         return report