Returns NIC attachements.

        :param maximum_adapters: maximum number of supported adapters
        :returns: list of adapters with their Attachment setting (NAT, bridged etc.)

def _get_nic_attachements(self, maximum_adapters):
        """
        Returns NIC attachements.

        :param maximum_adapters: maximum number of supported adapters
        :returns: list of adapters with their Attachment setting (NAT, bridged etc.)
        """

        nics = []
        vm_info = yield from self._get_vm_info()
        for adapter_number in range(0, maximum_adapters):
            entry = "nic{}".format(adapter_number + 1)
            if entry in vm_info:
                value = vm_info[entry]
                nics.append(value.lower())
            else:
                nics.append(None)
        return nics