I use jedi.el along with virtualenv-wrapper which does jump to definition perfectly fine ime. But keep an eye for open sourcegraph's mode[0], they are going incorporate python soon AFAIU.
One of the authors of srclib here. Python has been incorporated (and should be installed if you update srclib and run the toolchain install script). The website hasn't been updated to reflect this, however. Let us know if you run into any issues!