Inserting strings into lists in Python (v. 3.4.2)

I am learning about Functions and Classes in Python 3.4.2, and I got a little sidetracked by the output from this code snippet:

print("This program will collect your demographic information and output it")
print ("")

class Demographics:   #This class contains functions to collect demographic info 

    def phoneFunc():  #This function will collect user's PN, including area code
        phoneNum = str(input("Enter your phone number, area code first "))
        phoneNumList = []
        phoneNumList[:0] = phoneNum
        #phoneNumList.insert(0, phoneNum) this is commented out b/c I tried this and it made the next two lines insert the dash incorrectly

        phoneNumList.insert(3, '-')
        phoneNumList.insert(7, '-')
        print(*phoneNumList)

x = Demographics
x.phoneFunc()

When it prints the phone number, it spaces the digits out like this: x x x - x x x - x x x x rather than xxx-xxx-xxxx.

Is there a way to remove the spaces between the characters? I've looked at these threads (the first one was the most helpful, and got me partly on my way) but I suspect my problem isn't exactly the same as what's described in them:

Inserting a string into a list without getting split into characters

Split string into a list in Python

python 3.4.2 joining strings into lists