(Tkinter) Command executed automatically when binding, binding not acting as expected

Question

I am trying to bind a key to a command conditionally. But when I bind, the command gets automatically executed (when I toggle both commands). Why does that happen? And how can I only bind a command without executing it? Also after binding both commands, only the first one (function p) is being executed. Why is that? My code is as follows:

from tkinter import *
top = Tk()
editor = Text(top)
editor.pack()

def br(event=None):
    try:
        editor.insert(INSERT, "<br />")
    except:
        pass
def ins_br():
    br()
    return 'break'
def p(event=None):
    try:
        editor.insert(INSERT, "\n<p></p>")
        return 'break'
    except:
        pass
def br_and_p(event=None):
    br()
    p()
def enter_key():
    if ins_br_var.get() == 1 and p_var.get() == 1:
        editor.bind('<Return>', br_and_p())
    elif ins_br_var.get() == 1 and p_var.get() == 0:
        editor.bind('<Return>', br)
    elif ins_br_var.get() == 0 and p_var.get() == 1:
        editor.bind('<Return>', p)
    else:
        editor.unbind('<Return>')

toolbar = Frame(top, bd=1, relief=RAISED)
toolbar.pack(side=TOP, fill=X)
ins_br_var = IntVar()
ins_br_cbox = Checkbutton(toolbar, text="ins_br", variable=ins_br_var, command=enter_key)
ins_br_cbox.pack(side=LEFT, padx=2, pady=2)
p_var = IntVar()
p_cbox = Checkbutton(toolbar, text="p", variable=p_var, command=enter_key)
p_cbox.pack(side=LEFT, padx=2, pady=2)

Answer 1

Omit the ().

When you do this:

editor.bind('<Return>', br_and_p())

... You are immediately executing the function br_and_ p, and binding the result of that function to the event.