run black on codebase

ziffers/common.py

@@ -1,14 +1,19 @@
 def flatten(arr) -> list:
-    ''' Flattens array'''
-    return flatten(arr[0]) + (flatten(arr[1:]) if len(arr) > 1 else []) if type(arr) is list else [arr]
+    """Flattens array"""
+    return (
+        flatten(arr[0]) + (flatten(arr[1:]) if len(arr) > 1 else [])
+        if type(arr) is list
+        else [arr]
+    )
+
 
 def sum_dict(arr) -> dict:
-    ''' Sums array of dicts: [{a:3,b:3},{b:1}] -> {a:3,b:4} '''
+    """Sums array of dicts: [{a:3,b:3},{b:1}] -> {a:3,b:4}"""
     result = arr[0]
     for hash in arr[1:]:
-         for key in hash.keys():
+        for key in hash.keys():
             if key in result:
                 result[key] = result[key] + hash[key]
             else:
                 result[key] = hash[key]
-    return result
+    return result