def sample_template_checks(study_id, user, check_exists=False):
    """Performs different checks and raises errors if any of the checks fail

    Parameters
    ----------
    study_id : int
        The study id
    user : qiita_db.user.User
        The user trying to access the study
    check_exists : bool, optional
        If true, check if the sample template exists

    Raises
    ------
    HTTPError
        404 if the study does not exist
        403 if the user does not have access to the study
        404 if check_exists == True and the sample template doesn't exist
    """
    try:
        study = Study(int(study_id))
    except QiitaDBUnknownIDError:
        raise HTTPError(404, reason='Study does not exist')
    if not study.has_access(user):
        raise HTTPError(403, reason='User does not have access to study')

    # Check if the sample template exists
    if check_exists and not SampleTemplate.exists(study_id):
        raise HTTPError(404, reason="Study %s doesn't have sample information"
                        % study_id)