tkinter_app5.py

# creating the entries for the user input, FROM, TO and dates
from_city_entry = tk.Entry(frame_main_1, textvariable = from_city1, width=4)
from_city_entry.bind("<KeyRelease>", caps_from) # everytime a key is released, it runs the caps_from function on the cell

to_city_entry = tk.Entry(frame_main_2, textvariable = to_city1, width=4)
to_city_entry.bind("<KeyRelease>", caps_to) # everytime a key is released, it runs the caps_to function on the cell

departure_date_entry = tk.Entry(frame_main_1, textvariable = departure_date1, width=12)
return_date_entry = tk.Entry(frame_main_2, textvariable = return_date1, width=12)

# and we pack the two frames in the center_frame and then the elements inside them
frame_main_1.pack(fill='x', pady=2)
frame_main_2.pack(fill='x',pady=2)
#
# the order which we pack the items is important
from_city.pack(side='left')
from_city_entry.pack(side='left', padx=1)
departure_date.pack(side='left', padx=5)
departure_date_entry.pack(side='left')
to_city.pack(side='left')
to_city_entry.pack(side='left', padx=1)
return_date_entry.pack(side='right')
return_date.pack(side='right', padx=5)