found and fixed 2 bugs in derivatives substitutions
tree4c9baf0935ad1270ef1dcadb1fabcbc29f69f402
-rw-r--r-- 1503 LICENSE
-rw-r--r-- 139 MANIFEST.in
-rw-r--r-- 2966 README
-rw-r--r-- 189 TODO
drwxr-xr-x - bin
drwxr-xr-x - doc
drwxr-xr-x - examples
-rwxr-xr-x 7894 setup.py
drwxr-xr-x - sympy