'Returns folder size for current folder'

def get_folder_size(self, folder=None):

    if (not folder):
        folder = self.name
    file_size = frappe.db.sql(u'select    sum(ifnull(file_size,0))\n DCTB  DCTB  DCTB from    tabFile    where    folder=%s    ', folder)[0][0]
    return file_size
