def _set_mtu_to_nics(self, conf):
for dom_name, dom_spec in list(conf.get('<STR_LIT>', {}).items()):<EOL><INDENT>for idx, nic in enumerate(dom_spec.get('<STR_LIT>', [])):<EOL><INDENT>net = self._get_net(conf, dom_name, nic)<EOL>mtu = net.get('<STR_LIT>', <NUM_LIT>)<EOL>if mtu != <NUM_LIT>:<EOL><INDENT>nic['<STR_LIT>'] = mtu<EOL><DEDENT><DEDENT><DEDENT>
For all the nics of all the domains in the conf that have MTU set,
save the MTU on the NIC definition.

Args:
    conf (dict): Configuration spec to extract the domains from

Returns:
    None