Write a function to convert snake case string to camel case string.
def snake_to_camel(word):
        import re
        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 snake case string to camel case string.
def snake_to_camel(word):
        import re
        return ''.join(x.capitalize() or '_' for x in word.split('_'))[/INST]assert snake_to_camel('python_program')=='PythonProgram'
assert snake_to_camel('python_language')==('PythonLanguage')
assert snake_to_camel('programming_language')==('ProgrammingLanguage')</s>