def fetch_tickers(self, symbols=None, params={}):
    self.raise_error(NotSupported, details='API does not allow to fetch all tickers at once with a single call to fetch_tickers() for now')
def fetch_tickers(self, symbols=None, params={}):
    self.raise_error(NotSupported, details='API does not allow to fetch all tickers at once with a single call to fetch_tickers() for now')