def agp_transform(frame, study_id):
    """If the prep belongs to the American Gut Project fill in some blanks

    Parameters
    ----------
    frame: pd.DataFrame
        The preparation file for a single project.
    study_id: str
        The Qiita study identifier for this preparations.

    Returns
    -------
    pd.DataFrame:
        If the study_id is "10317" then the `center_name`,
        'library_construction_protocol', and `experiment_design_description`
        columns are filled in with default values. Otherwise no changes are
        made to `frame`.
    """
    if study_id == '10317':
        frame['center_name'] = 'UCSDMI'
        frame['library_construction_protocol'] = 'Knight Lab KHP'
        frame['experiment_design_description'] = (
            'samples of skin, saliva and feces and other samples from the AGP')
    return frame