Write a function to convert the given snake case string to camel case string by using regex.
import re
def snake_to_camel(word):
  return ''.join(x.capitalize() or '_' for x in word.split('_'))
<s>[INST]<<SYS>>Given a task and its code, generate test cases for the code.<</SYS>>Write a function to convert the given snake case string to camel case string by using regex.
import re
def snake_to_camel(word):
  return ''.join(x.capitalize() or '_' for x in word.split('_'))[/INST]assert snake_to_camel('android_tv') == 'AndroidTv'
assert snake_to_camel('google_pixel') == 'GooglePixel'
assert snake_to_camel('apple_watch') == 'AppleWatch'</s>