Docs for SQLFORM.accepts.im_class

    SQLFORM is used to map a table (and a current record) into an HTML form

    given a SQLTable stored in db.table

    generates an insert form::

        SQLFORM(db.table)

    generates an update form::

        record=db.table[some_id]
        SQLFORM(db.table, record)

    generates an update with a delete button::

        SQLFORM(db.table, record, deletable=True)

    if record is an int::

        record=db.table[record]

    optional arguments:

    :param fields: a list of fields that should be placed in the form,
        default is all.
    :param labels: a dictionary with labels for each field, keys are the field
        names.
    :param col3: a dictionary with content for an optional third column
            (right of each field). keys are field names.
    :param linkto: the URL of a controller/function to access referencedby
        records
            see controller appadmin.py for examples
    :param upload: the URL of a controller/function to download an uploaded file
            see controller appadmin.py for examples

    any named optional attribute is passed to the <form> tag
            for example _class, _id, _style, _action, _method, etc.