From 93c4512bcbaf9119c3c0e6798042e4d9ba69259f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bogumi=C5=82=20Kami=C5=84ski?= <bkamins@sgh.waw.pl>
Date: Wed, 28 Oct 2020 08:14:26 +0100
Subject: [PATCH] Update src/abstractdataframe/sort.jl

---
 src/abstractdataframe/sort.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/abstractdataframe/sort.jl b/src/abstractdataframe/sort.jl
index 5d4001d76a..39d7a9c438 100644
--- a/src/abstractdataframe/sort.jl
+++ b/src/abstractdataframe/sort.jl
@@ -473,7 +473,7 @@ julia> sortperm(df, (:x, :y), rev=true)
 """
 function Base.sortperm(df::AbstractDataFrame, cols=[];
                   alg=nothing, lt=isless, by=identity, rev=false, order=Forward)
-    if !(isa(by, Function) || (by isa AbstractVector && eltype(by) <: Function))
+    if !(by isa Base.Callable || (by isa AbstractVector && eltype(by) <: Base.Callable))
         msg = "'by' must be a Function or a vector of Functions. " *
               " Perhaps you wanted 'cols'."
         throw(ArgumentError(msg))