Python CLI app for tracking budget

I’m making a CLI app for myself for tracking my budget. How can I improve this code? One glitch I’m still trying to find out is when I hit return accidentally, it gives an error. I do not know how to get around it yet.

#!/usr/bin/python3  def t_lines():     import os     terminal_size = os.get_terminal_size()     print("-" * terminal_size.columns)   def main():     import sqlite3 as sql      conn = sql.connect("expenses.db")     cur = conn.cursor()      cur.execute("CREATE TABLE IF NOT EXISTS expenses \             (Date TEXT DEFAULT \"x\", \             item TEXT DEFAULT \"x\", \             category TEXT DEFAULT \"x\", \             Price REAL DEFAULT 0, \             Type TEXT DEFAULT \"e\")" )      t_lines()      print("Enter in the following format")      print("Enter 0 to quit")      print("Date (dd/mmm/yy), Item, Category, Price, Type ([e]xpense/[i]ncome)")      print("Example:")     print("12/nov/18, carrot, vegetable, 15.64, e")     print("13/aug/18, salary, work, 10000, income")      t_lines()      user_input = input()      vals = user_input.split(',')      while user_input != "0":         vals = user_input.split(',')         cur.execute("INSERT INTO expenses \                 VALUES (?, ?, ?, ?, ?)", vals)         conn.commit()         user_input = input()       conn.close()  if __name__ == '__main__':     main()