added a docstring

inventory_provider/juniper.py

@@ -322,6 +322,14 @@ def local_interfaces(
         type=netifaces.AF_INET,
         omit_link_local=True,
         omit_loopback=True):
+    """
+    generator yielding IPv4Interface or IPv6Interface objects,
+    depending on the value of type
+    :param type: hopefully AF_INET or AF_INET6
+    :param omit_link_local: skip v6 fe80* addresses if true
+    :param omit_loopback: skip lo* interfaces if true
+    :return:
+    """
     for n in netifaces.interfaces():
         if omit_loopback and re.match(r'^lo\d+', n):
             continue