diff --git a/letsencrypt/client/acme.py b/letsencrypt/client/acme.py
index dcd8157e3..392546b29 100644
--- a/letsencrypt/client/acme.py
+++ b/letsencrypt/client/acme.py
@@ -115,8 +115,8 @@ def authorization_request(req_id, name, server_nonce, responses, key_file):
 def certificate_request(csr_der, key):
     """Create ACME "certificateRequest" message.
 
-    :param csr_der: TODO
-    :type csr_der: TODO
+    :param csr_der: DER encoded CSR.
+    :type csr_der: str
 
     :param key: TODO
     :type key: TODO
@@ -127,7 +127,7 @@ def certificate_request(csr_der, key):
     """
     return {
         "type": "certificateRequest",
-        "csr": le_util.jose_b64encode(csr_der),  # TODO: csr_der.encode?
+        "csr": le_util.jose_b64encode(csr_der),
         "signature": crypto_util.create_sig(csr_der, key),
     }
 
@@ -148,7 +148,7 @@ def revocation_request(key_file, cert_der):
     """
     return {
         "type": "revocationRequest",
-        "certificate": le_util.jose_b64encode(cert_der),  # TODO: csr_der.encode?
+        "certificate": le_util.jose_b64encode(cert_der),
         "signature": crypto_util.create_sig(cert_der, key_file),
     }
 
diff --git a/letsencrypt/client/client.py b/letsencrypt/client/client.py
index 590714d6f..43e3ae17e 100644
--- a/letsencrypt/client/client.py
+++ b/letsencrypt/client/client.py
@@ -161,8 +161,8 @@ class Client(object):
     def acme_certificate(self, csr_der):
         """Handle ACME "certificate" phase.
 
-        :param csr_der: TODO
-        :type csr_der: TODO
+        :param csr_der: CSR in DER format.
+        :type csr_der: str
 
         :returns: ACME "certificate" message.
         :rtype: dict
@@ -593,11 +593,22 @@ class Client(object):
         return challenge_objs, challenge_obj_indices
 
     def get_key_csr_pem(self, csr_return_format='der'):
-        """
-        Returns key and CSR using provided files or generating new files if
-        necessary. Both will be saved in pem format on the filesystem.
-        The CSR can optionally be returned in DER format as the CSR cannot be
-        loaded back into M2Crypto.
+        """Return key and CSR, generate if necessary.
+
+        Returns key and CSR using provided files or generating new files
+        if necessary. Both will be saved in PEM format on the
+        filesystem. The CSR can optionally be returned in DER format as
+        the CSR cannot be loaded back into M2Crypto.
+
+        :param csr_return_format: If "der" returned CSR is in DER format,
+                                  PEM otherwise.
+        :param csr_return_format: str
+
+        :returns: A pair of `(key, csr)`, where `key` is PEM encoded `str`
+                  and `csr` is PEM/DER (depedning on `csr_return_format`
+                  encoded `str`.
+        :rtype: tuple
+
         """
         key_pem = None
         csr_pem = None