Trying To make a function in Python

I want to make a function called
helloWorld() that will return "Hello World!" if it has no input and whatever string you put if it does. It also has a stack argument that, if set to true, will cause the string to be printed in a column. If you set stack to true and set c to any number, that number of characters should be on each line, and no line should repeat characters. I currently have this code:

 def helloWorld(text="Hello World!",stack=False,c=1,printResult=False):
  # If the user inputs a value that isn't a string, make it a string and assign it to "s".
  s=str(text)
  li=0
  # Check if the "stack" argument is True.
  if stack==True:
    # Set char to be the amount of lines that need to be returned.
    char=range(int(len(s)/c))
    # Set up the first line.
    r=[s[:c]]
    # Loop through char to print each line.
    for x in char:
      if x==0:
        continue
      else:
        r.insert(len(r),s[x:x*3])
        li=+1
    # If "stack" is False then set r to be s.
  else:
    r=s
  line=range(li)
  if printResult==True:
    for x in line:
      print(r[x])
  else:
    return(r)

print(helloWorld(stack=True,c=3,printResult=False))

if printResult is false like shown, then it just doesn't print the result automatically and instead returns a list. printResult being set to true should make it print the text in a column if it is set to do that, but it doesn't seem to do that.