问TypeError: append()只接受一个参数(0给定)，如何解决？

EN

##code##
name = input("hello user what is your name?")
print("thank you for using our program:",name.title(),)
userchoice = input("which program would you like to use: add numbers,minus 
numbers, alphabetical word order?")
#add numbers#
numList = []
addnewnumber = input ("would you like to add a new number?")
while addnewnumber == 'yes':
    newnumber = input("what is your number?")
    numList.append()
if addnewnumber == 'no':
    numListsum = sum(numList)
    print (numListsum)

 ##Console message##
RESTART: C:/Users/SWILS/AppData/Local/Programs/Python/Python36/python 
coding/1.0.py 
hello user what is your name?sean
thank you for using our program: Sean
which program would you like to use: add numbers,minus numbers, alphabetical 
word order?add numbers
would you like to add a new number?yes
what is your number?6
Traceback (most recent call last):
File "C:/Users/SWILS/AppData/Local/Programs/Python/Python36/python 
coding/1.0.py", line 11, in <module>
numList.append()
TypeError: append() takes exactly one argument (0 given)