chore: import upstream snapshot with attribution

mla/metrics/base.py

@@ -0,0 +1,25 @@
+# coding:utf-8
+import numpy as np
+
+
+def check_data(a, b):
+    if not isinstance(a, np.ndarray):
+        a = np.array(a)
+
+    if not isinstance(b, np.ndarray):
+        b = np.array(b)
+
+    if type(a) != type(b):
+        raise ValueError("Type mismatch: %s and %s" % (type(a), type(b)))
+
+    if a.size != b.size:
+        raise ValueError("Arrays must be equal in length.")
+    return a, b
+
+
+def validate_input(function):
+    def wrapper(a, b):
+        a, b = check_data(a, b)
+        return function(a, b)
+
+    return wrapper