'Return new FormDefinition field.'

def new(self, name=None, label=None, required=False, helptext=None, default=None, visible=True, layout=None):

    rval = {}
    assert name, 'Must    provide    a    name'
    rval['name'] = name
    if (not label):
        rval['label'] = name
    else:
        rval['label'] = label
    if required:
        rval['required'] = 'required'
    else:
        rval['required'] = 'optional'
    if (helptext is None):
        helptext = ''
    rval['helptext'] = helptext
    if (default is None):
        default = ''
    rval['default'] = default
    rval['visible'] = visible
    rval['layout'] = layout
    return rval
