(value)
return value.bit_length() - 1
returns index of highest bit, or -1 if value is zero or negative
returns index of highest bit, or -1 if value is zero or negative
returns index of highest bit or - 1 if value is zero or negative
def _high_bit(value):
    """
    returns index of highest bit, or -1 if value is zero or negative
    """
    return value.bit_length() - 1
def _high_bit ( value ) : return value . bit_length ( ) - 1