diff --git a/src/types.jl b/src/types.jl
index 313d426..3613881 100644
--- a/src/types.jl
+++ b/src/types.jl
@@ -89,6 +89,7 @@ end
 
 Base.zero(a::AlgebraElement) = (b = similar(a); return MA.operate!(zero, b))
 Base.one(a::AlgebraElement) = one(eltype(a), parent(a))
+# `iszero(coeffs(a))` doesn't work if `coeffs(a) isa Tuple`
 Base.iszero(a::AlgebraElement) = all(iszero, coeffs(a))
 
 function Base.isone(a::AlgebraElement)