input: Write a function to generate a star pattern where the stars first increase in number across 5 lines, and then decrease across the next 5 lines. The function should take an integer input representing the number of lines in each section of the pattern. If no input is given, it defaults to 5.
  assert generate_star_pattern(5) == None
  assert generate_star_pattern(3) == None
output: def generate_star_pattern(n=5):
      for i in range(1, n + 1):
          print('*' * i)
      for i in range(n - 1, 0, -1):
          print('*' * i)