How to use the fastparquet.api.ParquetFile function in fastparquet

"""Read a single file with fastparquet, to be used in a task"""
    from fastparquet.api import ParquetFile
    from collections import OrderedDict

    name_storage_mapping = {v: k for k, v in storage_name_mapping.items()}
    if not isinstance(columns, (tuple, list)):
        columns = [columns]
        series = True
    if index:
        index, = index
        if index not in columns:
            columns = columns + [index]
    columns = [name_storage_mapping.get(col, col) for col in columns]
    index = name_storage_mapping.get(index, index)
    cs = OrderedDict([(k, v) for k, v in cs.items() if k in columns])
    pf = ParquetFile(fn, open_with=fs.open)
    pf.file_scheme = scheme
    for rg in pf.row_groups:
        for ch in rg.columns:
            ch.file_path = fn.replace(base, "").lstrip("/")
    pf.fn = base
    df = pf.to_pandas(columns=columns, index=index, categories=categories)

    if df.index.nlevels == 1:
        if index:
            df.index.name = storage_name_mapping.get(index, index)
    else:
        if index:
            df.index.names = [storage_name_mapping.get(name, name) for name in index]
    df.columns = [storage_name_mapping.get(col, col) for col in columns if col != index]

    if series: