def to_camel_case(snake_str):
    """
    Transforms a snake_case string into camelCase.

    Parameters
    ----------
    snake_str : str

    Returns
    -------
    str
    """
    parts = snake_str.split("_")
    # We capitalize the first letter of each component except the first one
    # with the 'title' method and join them together.
    return parts[0] + "".join(x.title() for x in parts[1:])