fixup! Improve asymmetric key check in CryptographyHMACKey

Author: danigm

jose/backends/cryptography_backend.py

@@ -56,6 +56,11 @@
 
 
 def is_pem_format(key):
+    """
+    Return True if the key is PEM format
+    This function uses the list of valid PEM headers defined in
+    _PEMS dict.
+    """
     return bool(_PEM_RE.search(key))
 
 
@@ -73,6 +78,11 @@ def is_pem_format(key):
 
 
 def is_ssh_key(key):
+    """
+    Return True if the key is a SSH key
+    This function uses the list of valid SSH key format defined in
+    _SSH_KEY_FORMATS dict.
+    """
     if any(string_value in key for string_value in _SSH_KEY_FORMATS):
         return True