How to properly implement openpyxl and csvwriter in AWS with S3 bucket as input directory

Question

I was using this code to process an excel file in Python on my local machine where input_dir was my input directory and file was just the file I wanted to grab from that directory:

input_file = input_dir + file

def excel_to_csv(input_file):    
    #open workbook and store excel object
    excel = openpyxl.load_workbook(input_file)

    #select active sheet
    sheet = excel["PUBLISH"]

    #create writer object
    col = csv.writer(open("tt.csv",'w', newline=""))

    #write data to csv
    for r in sheet.rows:
        col.writerow([cell.value for cell in r])
#Convert CSV to dataframe
excel_to_csv(input_file)        
jpm = pd.DataFrame(pd.read_csv("tt.csv", header = 11, usecols = [*range(1,16)]))

However when I tried to migrate this to AWS using an S3 bucket as the source directory, the code fails. I know it is because I need to use an io.BytesIO object to accomplish this, but I am very much unversed in AWS and am not sure how to use openpyxl and csv.writer in the AWS environment.