Return a string with the callable signature and its docstring.

    :param the_callable: the callable to be analyzed.
    :type the_callable: function/callable.
    :return: the signature.

def get_callable_documentation(the_callable):
    """Return a string with the callable signature and its docstring.

    :param the_callable: the callable to be analyzed.
    :type the_callable: function/callable.
    :return: the signature.
    """
    return wrap_text_in_a_box(
        title=get_callable_signature_as_string(the_callable),
        body=(getattr(the_callable, '__doc__') or 'No documentation').replace(
            '\n', '\n\n'),
        style='ascii_double')