Possible to append multiple lists at once? (Python)

I have a bunch of lists I want to append to a single list that is sort of the “main” list in a program I’m trying to write. Is there a way to do this in one line of code rather than like 10? I’m a beginner so I have no idea…

For a better picture of my question, what if I had these lists:

x = [1, 2, 3]
y = [4, 5, 6]
z = [7, 8, 9]

And want to append y and z to x. Instead of doing:

x.append(y)
x.append(z)

Is there a way to do this in one line of code? I already tried:

x.append(y, z)

And it wont work.

Answer

x.extend(y+z)

should do what you want

or

x += y+z

or even

x = x+y+z