Im using the pymel.core.mel -class in order to run a command only available in MEL, but it whines at my syntax and the official docs are of no help:
import pymel.core as pm
myPath = "C:\Users\Martin\Desktop\lolk\mrlolk.fbx"
pm.mel.FBXExport(filename=myPath, s=True)
Doc on the MEL command: http://download.autodesk.com/global/docs/maya2014/en_us/index.html?url=files/GUID-E85FCD1E-57BE-48FF-9D46-ED64091562B1.htm,topicNumber=d30e145806
Doc on pymel.core.mel: http://download.autodesk.com/us/maya/2011help/PyMel/generated/classes/pymel.core.language/pymel.core.language.Mel.html