Set vCard field values and parameters on a new vCard.

def SetVcardField(new_vcard, field_name, values):
    """Set vCard field values and parameters on a new vCard."""
    for val in values:
        new_field = new_vcard.add(field_name)
        new_field.value = val.value
        if val.params:
            new_field.params = val.params
    return new_vcard