import base64

from io import BytesIO

import pandas as pd

from io import StringIO

import openpyxl

def main(csv_bytes: bytes) -> str:

    # Convert bytes to string

    csv_string = csv_bytes.decode('utf-8')

    # Use StringIO to convert string to a file-like object for reading into DataFrame

    csv_file = StringIO(csv_string)

    # Read CSV data into DataFrame

    df = pd.read_csv(csv_file)

    # Convert DataFrame to Excel and save to a BytesIO object

    excel_buffer = BytesIO()

    df.to_excel(excel_buffer, index=False)

    excel_buffer.seek(0)  # Rewind the buffer to the beginning

    # Encode the Excel file into a base64 string

    base64_excel = base64.b64encode(excel_buffer.read()).decode('utf-8')

    return { "file": { "content": base64_excel, "filename": "data.xlsx" } }