def __init__(self, app: Flask, html_layout_file: str, spec_file: str,
graph_layout_file: str, data_spec_file: str, tooltip_file: str,
time_period: int=None) -> None:
def __init__(self, app: Flask, html_layout_file: str, spec_file: str,
graph_layout_file: str, data_spec_file: str, tooltip_file: str,
time_period: int=None) -> None: