'Noting row boundaries, see if we can return to the starting point.'

def scan_up(self, top, left, bottom, right):

    rowseps = {}
    for i in range((bottom - 1), top, (-1)):
        if (self.block[i][left] == '+'):
            rowseps[i] = [left]
        elif (self.block[i][left] != '|'):
            return None
    return rowseps
