def flatten(s, accepted_types=(list, tuple)):
    """flatten lists and tuples to a single list, ignore empty
    
    Parameters
    ----------
    s       :    Sequence
    accepted_types  :    Tuple (acceptable sequence types, default (list,tuple)
    
    Return
    ------
    l       :    Flat sequence
    
    Example
    -------
    flatten(('Hello',[' ',2],[' '],(),['the',[([' '])],('World')]))
    ('Hello', ' ', 2, ' ', 'the', ' ', 'World')
    """
    s_type = type(s)
    s = list(s)
    i = 0
    while i < len(s):
        while isinstance(s[i], accepted_types):
            if not s[i]:
                s.pop(i)
                i -= 1
                break
            else:
                s[i:i+1] = s[i]
        i += 1
    return s_type(s)