diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md
index f7aa1c6d7..5c6718137 100644
--- a/specs/core/0_beacon-chain.md
+++ b/specs/core/0_beacon-chain.md
@@ -1028,7 +1028,7 @@ def is_power_of_two(value: int) -> bool:
     """
     Check if ``value`` is a power of two integer.
     """
-    return (value > 0) && (value & (value - 1) == 0)
+    return (value > 0) and (value & (value - 1) == 0)
 ```
 
 ### `int_to_bytes1`, `int_to_bytes2`, ...