NetworkManager/introspection/nm-ppp-manager.xml

<?xml version="1.0" encoding="UTF-8" ?>

<node name="/">
  <interface name="org.freedesktop.NetworkManager.PPP">
    <annotation name="org.gtk.GDBus.C.Name" value="PPP_Manager"/>

    <method name="NeedSecrets">
      <annotation name="org.freedesktop.DBus.GLib.CSymbol" value="impl_ppp_manager_need_secrets"/>
      <annotation name="org.freedesktop.DBus.GLib.Async" value=""/>
      <arg name="username" type="s" direction="out"/>
      <arg name="password" type="s" direction="out"/>
    </method>

    <method name="SetIp4Config">
      <annotation name="org.freedesktop.DBus.GLib.CSymbol" value="impl_ppp_manager_set_ip4_config"/>
      <arg name="config" type="a{sv}" direction="in"/>
    </method>

    <method name="SetIp6Config">
      <annotation name="org.freedesktop.DBus.GLib.CSymbol" value="impl_ppp_manager_set_ip6_config"/>
      <arg name="config" type="a{sv}" direction="in"/>
    </method>

    <method name="SetState">
      <annotation name="org.freedesktop.DBus.GLib.CSymbol" value="impl_ppp_manager_set_state"/>
      <arg name="state" type="u" direction="in"/>
    </method>
  </interface>
</node>