The setKeyPath command either creates or edits the path (a nurbs curve) based on the current position of the selected object at the current time.
Derived from mel command maya.cmds.setKeyPath
Example:
import pymel.core as pm
import maya.cmds as cmds
# Apply setKeyPath command on the currently selected object at current time:
pm.setKeyPath()
# Apply setKeyPath command on an object named "ball" at current time:
pm.setKeyPath( 'ball' )