@staticmethod
def safe_float_2(dictionary, key1, key2, default_value=None):
    return Exchange.safe_either(Exchange.safe_float, dictionary, key1, key2, default_value)
@staticmethod
def safe_float_2(dictionary, key1, key2, default_value=None):
    return Exchange.safe_either(Exchange.safe_float, dictionary, key1, key2, default_value)