Fix attack cache tests

binding/python_c_ffi.py

@@ -100,6 +100,13 @@ def get_rank_mask(rank):
     return sum(1 << (rank*8 + f) for f in range(8))
 
 
+def bb_from(*algebraic):
+    m = 0
+    for s in algebraic:
+        m |= (1 << sq(s))
+    return m
+
+
 class ChessFFI:
     def __init__(self):
         self.lib_path = "./build/libchess.so"