'Unblock interface if it is blocked
:param self: A NetworkManager object
:param interface_name: Name of an interface
:type self: NetworkManager
:type interface_name: str
:return: None
:rtype: None'

def unblock_interface(self, interface_name):

    card = self._name_to_object[interface_name].card
    if pyw.isblocked(card):
        pyw.unblock(card)
