input: Write a function to print a formatted table of grades for a given set of students where each student is represented as a dictionary containing their name and grade. If the input list is empty, the function should print a single line indicating no students available.
  assert print_grade_table([{'name': "John", 'grade': 92}, {'name': "Alice", 'grade': 95}, {'name': "Bob", 'grade': 87}])==None
  assert print_grade_table([])==None
output: def print_grade_table(students):
      if not students:
          print("no students available")
      else:
          print("Name  | Grade")
          print("-------------")
          for student in students:
              print(f"{student['name']:<6}| {student['grade']}")