def to_camel_case(snake_str):    words = snake_str.split('_')    return words[0] + ''.join(w.capitalize() for w in words[1:])def to_snake_case(camel_str):    s1 = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', camel_str)    return re.sub('([a-z0-9])([A-Z])', r'\1_\2', s1).lower()

 str1 = 'portMapping'

str2 = 'port_mapping'

> to_camel_case(str2)

> portMapping

> to_snake_case(str1)

>port_mapping