How do I save a file generated in a notebook to a lakehouse?

I've just started working with Microsoft Fabric for the first time coming from a long career in software, architecture, and data science at a much lower level--I'm definitely more comfortable with terminal than UIs for technical work.  Here's one example why:

I have a scenario in which I have loaded CSV data into a lakehouse, then load it into a Delta-Parquet table.  Assume I perform some transformation on that into another table, then I want to generate an Excel file (NOT a CSV file) from a python notebook using a package like `xlsxwriter`, which includes formatting and formulas in addtion to data.

How do I save that output `*.xlsx` file to a retrievable location, such as the same lakehouse I loaded the original CSV file to?

More specifically, suppose I have a notebook open in a Fabric workspace and execute:

expenses = (
    ['Rent', 1000],
    ['Gas',   100],
    ['Food',  300],
    ['Gym',    50],
)

!pip install xlsxwriter
import xlsxwriter

# Create a workbook and add a worksheet.
workbook = xlsxwriter.Workbook('Expenses01.xlsx')
worksheet = workbook.add_worksheet()

# Some data we want to write to the worksheet.
expenses = (
    ['Rent', 1000],
    ['Gas',   100],
    ['Food',  300],
    ['Gym',    50],
)

# Start from the first cell. Rows and columns are zero indexed.
row = 0
col = 0

# Iterate over the data and write it out row by row.
for item, cost in (expenses):
    worksheet.write(row, col,     item)
    worksheet.write(row, col + 1, cost)
    row += 1

# Write a total using a formula.
worksheet.write(row, 0, 'Total')
worksheet.write(row, 1, '=SUM(B1:B4)')
workbook.close()

I know from this that the file is created:

# We created an Excel file, but where is it?

import os
files = [f for f in os.listdir('.') if os.path.isfile(f)]
files

because the print statement shows it:

['container_tokens',
 '.launch_container.sh.crc',
 'default_container_executor.sh',
 'default_container_executor_session.sh',
 'launch_container.sh',
 '.container_tokens.crc',
 '.default_container_executor_session.sh.crc',
 '.default_container_executor.sh.crc',
 'Expenses01.xlsx']

 But I don't know how to retrieve that file or direct it to a retrievable location.