diff --git a/admin.py b/admin.py
index d4b3a92..a77d79f 100644
--- a/admin.py
+++ b/admin.py
@@ -35,6 +35,14 @@
 version = "0.0.0-DEV"
 banner = "Linaro VLANd admin interface, version %s" % version
 
+def is_positive(text):
+    if text in ('1', 'y', 'Y', 't', 'T', 'True'):
+        return True
+    elif text in ('0', 'n', 'N', 'f', 'F', 'False'):
+        return False
+    else:
+        raise InputError("Cannot parse \"%s\" as True or False" % text)
+
 def dump_switch(switch):
     print switch
 
@@ -280,13 +288,10 @@
     except InputError as inst:
         print 'Failed: %s' % inst
 elif opts.create_vlan is not None:
-    is_base = False
-    if opts.create_vlan[2] in ('1', 'y', 'Y'):
-        is_base = True
     try:
         vlan_id = db.create_vlan(opts.create_vlan[0],
                                  opts.create_vlan[1],
-                                 is_base)
+                                 is_positive(opts.create_vlan[2]))
         print 'Created vlan_id %d' % vlan_id
     except InputError as inst:
         print 'Failed: %s' % inst