fibonacci sequence closed form code example

Example: fibinachi

def fib(n):
  lisp = []
  
  for i in range(n):
    if len(lisp) < 3:
      if len(lisp) == 0:
        lisp.append(0)
      else:
        lisp.append(1)
    
    else:
      lisp.append(lisp[len(lisp)-1]+lisp[len(lisp)-2])
  
  return lisp