Return the network adapter type.

    adpater_type
        The adapter type from which to obtain the network adapter type.

def get_network_adapter_type(adapter_type):
    '''
    Return the network adapter type.

    adpater_type
        The adapter type from which to obtain the network adapter type.
    '''
    if adapter_type == 'vmxnet':
        return vim.vm.device.VirtualVmxnet()
    elif adapter_type == 'vmxnet2':
        return vim.vm.device.VirtualVmxnet2()
    elif adapter_type == 'vmxnet3':
        return vim.vm.device.VirtualVmxnet3()
    elif adapter_type == 'e1000':
        return vim.vm.device.VirtualE1000()
    elif adapter_type == 'e1000e':
        return vim.vm.device.VirtualE1000e()

    raise ValueError('An unknown network adapter object type name.')