OSError: [Errno 22] Invalid argument on CMD

Question

I keep getting OSError: [Errno 22] Invalid argument when I run my code in cmd. I have read that this can be done by replacing: and \ but this does not work. Maybe someone can see where I'm wrong.

import pandas as pd
import os
from openpyxl import load_workbook
import xlsxwriter
from shutil import copyfile
file=input('File Path: ')
extension = os.path.splitext(file)[1]
filename = os.path.splitext(file)[0]
pth=os.path.dirname(file)
newfile=os.path.join(pth,filename+'_2'+extension)
df=pd.read_excel(file)
colpick=input('Select Column: ')
cols=list(set(df[colpick].values))
def sendtofile(cols):
    for i in cols:
        df[df[colpick] == i].to_excel("{}/{}.xlsx".format(pth, i), sheet_name=i, index=False)
    print('\nCompleted')
    print('Thanks for using this program.')
    return
def sendtosheet(cols):
    copyfile(file, newfile)
    for j in cols:
        writer = pd.ExcelWriter(newfile, engine='openpyxl')
        for myname in cols:
            mydf = df.loc[df[colpick] == myname]
            mydf.to_excel(writer, sheet_name=myname, index=False)
        writer.save()
    print('\nCompleted')
    print('Thanks for using this program.')
    return
print('You data will split based on these values {} and create {} files or sheets based on next selection. If you are ready to proceed please type "Y" and hit enter. Hit "N" to exit.'.format(', '.join(cols),len(cols)))
while True:
    x=input('Ready to Proceed (Y/N): ').lower()
    if x == 'y':
        while True:
            s = input('Split into different Sheets or File (S/F): ').lower()
            if s == 'f':
                sendtofile(cols)
                break
            elif s == 's':
                sendtosheet(cols)
                break
            else: continue
        break
    elif x=='n':
        print('\nThanks for using this program.')
        break
    else: continue