(s)
return s in str
:type s: str
    :rtype: bool
:type s: str
    :rtype: bool
: type s : str : rtype : bool
def repeat_substring(s):
    """
    :type s: str
    :rtype: bool
    """
    str = (s + s)[1:-1]
    return s in str
def repeat_substring ( s ) : str = ( s + s ) [ 1 : - 1 ] return s in str