diff --git a/client-webserver/make-req.py b/client-webserver/make-req.py
index 13d3829c4..d8f0aa1db 100644
--- a/client-webserver/make-req.py
+++ b/client-webserver/make-req.py
@@ -4,10 +4,11 @@
 
 from M2Crypto import EVP, X509, RSA
 
-def mkreq(names, bits=2048):
+def make_request(names, bits=2048):
     """Return a tuple (key, csr) containing a PEM-formatted private key
     of the specified number of bits and a CSR requesting a certificate for
     the specified DNS names."""
+    assert names, "Must provide one or more hostnames."
     pk = EVP.PKey()
     x = X509.Request()
     rsa = RSA.gen_key(bits, 65537)