input: Write a python function to encode and decode a given text using base64 encoding.
  assert encode("Hello World!") == b'SGVsbG8gV29ybGQh'
  assert decode(b'SGVsbG8gV29ybGQh') == "Hello World!"
  assert encode("Python is fun") == b'UHl0aG9uIGlzIGZ1bg=='
  assert decode(b'UHl0aG9uIGlzIGZ1bg==') == "Python is fun"
output: import base64
  
  def encode(text):
      return base64.b64encode(text.encode('utf-8'))
  
  def decode(encoded_text):
      return base64.b64decode(encoded_text).decode('utf-8')