Acquiring process inside tag attribute values, (below which the label is to obtain a value of the property source-data-lazy-img) of
soup2 = BeautifulSoup(span.encode('utf-8'), 'html.parser')
for img2 in soup2.find_all('img',{"source-data-lazy-img":True}):
print img2["source-data-lazy-img"]
Source https://cloud.tencent.com/developer/ask/141071
Get has the property tag corresponding to the value of
print 'prices of commodities:' + img2.text