freqtrade_origin/freqtrade/data/datahandlers/__init__.py

from typing import Type

from .idatahandler import IDataHandler


def get_datahandlerclass(datatype: str) -> Type[IDataHandler]:
    """
    Get datahandler class.
    Could be done using Resolvers, but since this may be called often and resolvers
    are rather expensive, doing this directly should improve performance.
    :param datatype: datatype to use.
    :return: Datahandler class
    """

    if datatype == 'json':
        from .jsondatahandler import JsonDataHandler
        return JsonDataHandler
    elif datatype == 'jsongz':
        from .jsondatahandler import JsonGzDataHandler
        return JsonGzDataHandler
    else:
        raise ValueError(f"No datahandler for datatype {datatype} available.")