diff --git a/R/derekovecs_apicall_syn_nlc.R b/R/derekovecs_apicall_syn_nlc.R
index 93ab249..23bd92a 100644
--- a/R/derekovecs_apicall_syn_nlc.R
+++ b/R/derekovecs_apicall_syn_nlc.R
@@ -24,14 +24,14 @@
     content(response, as = 'parsed', type = 'application/json', simplifyDataFrame = TRUE)
   }
   else {
-    return(NA)
+    return(NULL)
   }
 }
 
 getW2VCollocates <- function(wordform = "Grund", ...) {
   ret<-DeReKoVecsCall(wordform, ...)
-  if(!is.na(ret)) ret$collocators
-  else NA
+  if(!is.null(ret)) ret$collocators
+  else NULL
 }
 
 getClassicCollocates <- function(wordform = "Grund") {
@@ -41,7 +41,7 @@
     content(response, as = 'parsed', type = 'application/json', simplifyDataFrame = TRUE)$collocates
   }
   else {
-    return(NA)
+    return(null)
   }
 }
 
@@ -49,7 +49,7 @@
 getBoth <- function(wordform = "Schmetterlinge") {
   w2v <- getW2VCollocates(wordform)
   classic <- getClassicCollocates(wordform)
-  if (length(w2v)>0 && length(classic>0) && !is.na(w2v) && !is.na(classic)) {
+  if (!is.null(w2v) && !is.null(classic)) {
     merge(classic,w2v,by="word",all=TRUE)
   }
   else {
@@ -58,7 +58,7 @@
 }
 
 getRanks <- function(collocates,NApenalty=1000) {
-  if (is.na(collocates)) {
+  if (is.null(collocates)) {
     return(NA)
   }
   both <<-