[utils] Introduce merge_dicts

youtube_dl/utils.py

@@ -2225,6 +2225,20 @@ def try_get(src, getter, expected_type=None):
                 return v
 
 
+def merge_dicts(*dicts):
+    merged = {}
+    for a_dict in dicts:
+        for k, v in a_dict.items():
+            if v is None:
+                continue
+            if (k not in merged or
+                    (isinstance(v, compat_str) and v and
+                        isinstance(merged[k], compat_str) and
+                        not merged[k])):
+                merged[k] = v
+    return merged
+
+
 def encode_compat_str(string, encoding=preferredencoding(), errors='strict'):
     return string if isinstance(string, compat_str) else compat_str(string, encoding, errors)