clarifying comment

Author: t-kalinowski

R/install.R

@@ -27,7 +27,7 @@ install_keras <- function(method = c("auto", "virtualenv", "conda"),
                           ...) {
 
   pkgs <- default_extra_packages(tensorflow)
-  if(!is.null(extra_packages))
+  if(!is.null(extra_packages)) # user supplied package version constraints take precedence
     pkgs[gsub("[=<>~]{1,2}[0-9.]+$", "", extra_packages)] <- extra_packages
 
   if(tensorflow == "default") # may be different from tensorflow