我需要帮助输出销售总收入（总和）最低的付款方式。现在，代码正在输出所有付款方式（Visa，万事达卡，Discover等）的总和，但是我只需要输出总金额最低的付款方式即可。
我已经收集了所有付款方式并计算了每种付款方式的总和，但是我在如何限制输出以仅显示总金额最低的付款方面遇到了麻烦。
"""
Python script to find the total amount of sales revenue for each payment mode
using Map-Reduce framework (mapper, combiner, and reducer functions) with mrjob package
"""
from mrjob.job import MRJob
class ModeRevenue(MRJob):
# each input lines consists of city, productCategory, price, and paymentMode
# Initialize the count value
count = 0
def mapper(self, _, line):
# create a key-value pair with key: paymentMode and value: price
line_cols = line.split(',')
yield line_cols[3], float(line_cols[2])
def combiner(self, mode, counts):
# consolidates all key-value pairs of mapper function (performed at mapper nodes)
yield mode, sum(counts)
def reducer(self, mode, counts):
# final consolidation of key-value pairs at reducer nodes
self.count += 1
if self.count <= 5:
yield mode, '${:,.2f}'.format(sum(counts))
if __name__ == '__main__':
ModeRevenue.run()
我需要将输出作为收入最低的一种付款方式，而不是全部。
预期：
"Discover" "$24,922,765.13"
实际：
"Amex" "$25,027,699.58"
"Cash" "$25,030,603.02"
"Discover" "$24,922,765.13"
"MasterCard" "$24,952,916.42"
"Visa" "$25,121,673.01"