add load_der_x509_csr to support loading DER encoded CSRs
diff --git a/docs/x509.rst b/docs/x509.rst
index 22b282c..dbfb441 100644
--- a/docs/x509.rst
+++ b/docs/x509.rst
@@ -118,6 +118,22 @@
:returns: An instance of
:class:`~cryptography.x509.CertificateSigningRequest`.
+.. function:: load_der_x509_csr(data, backend)
+
+ .. versionadded:: 0.9
+
+ Deserialize a certificate signing request (CSR) from DER encoded data. DER
+ is a binary format and is not commonly used with CSRs.
+
+ :param bytes data: The DER encoded request data.
+
+ :param backend: A backend supporting the
+ :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
+ interface.
+
+ :returns: An instance of
+ :class:`~cryptography.x509.CertificateSigningRequest`.
+
.. doctest::
>>> from cryptography import x509