As shown, the download button
Check its elements, is not directly targeted by xpath can not locate, turned firepath acquired CSS is invalid #downloadItems> a
But as after firepath , directly in html copy the following CSS is positioned can be used
html body div.pt.pt-right div.cont dl.newcodecontent dd#downloadItems a
Complete script
browser.find_element_by_css_selector("html body div.pt.pt-right div.cont dl.newcodecontent dd#downloadItems a").click()
Similar methods can be positioned with reference to this element