I am converting pandas dataframe to polars dataframe but pyarrow throws error.

My code:

import polars as pl
import pandas as pd

if __name__ == "__main__":

    with open(r"test.xlsx", "rb") as f:
        excelfile = f.read()
    excelfile = pd.ExcelFile(excelfile)
    sheetnames = excelfile.sheet_names
    df = pd.concat(
        [
            pd.read_excel(
            excelfile, sheet_name=x, header=0)
                    for x in sheetnames
                    ], axis=0)

    df_pl = pl.from_pandas(df)

Error:

File "pyarrow\array.pxi", line 312, in pyarrow.lib.array

File "pyarrow\array.pxi", line 83, in pyarrow.lib._ndarray_to_array

File "pyarrow\error.pxi", line 122, in pyarrow.lib.check_status

pyarrow.lib.ArrowTypeError: Expected bytes, got a 'int' object

I tried changing pandas dataframe dtype to str and problem is solved, but i don't want to change dtypes. Is it bug in pyarrow or am I missing something?