Merge all excel files into one csv file

Usage:

from merge_all_excel_sheet_to_csv import main

main( selected_columns='"Account Number","Premise","Service Address","Meter Number","Doc Amount in $","Usage in TGals","Billing Date","Due Date","Rate Category"', file_name="CY*.xlsx", file_prefix="CY", file_extension=".xlsx", top_rows=10, output_file="output", )