input: Write a function to generate sample data for a web application using Python's faker library. The output should contain three columns of data: name, email, and age. The function should take an integer parameter 'n' to specify the number of entries to generate, and should print each entry. If 'n' is not provided, the function should generate 10 entries by default.
  assert generate_sample_data() == None
  assert generate_sample_data(3) == None
  assert generate_sample_data(-1) == None
  
  from faker import Faker
  
  def generate_sample_data(n=10):
      fake = Faker()
      if n <= 0:
          return
      for _ in range(n):
          print(fake.name(), fake.email(), fake.random_int(min=18, max=60))
output: from faker import Faker
  
  def generate_sample_data(n=10):
      fake = Faker()
      if n <= 0:
          return
      for _ in range(n):
          print(fake.name(), fake.email(), fake.random_int(min=18, max=60))