@spiceErrorCheck<EOL>def spkpvn(handle, descr, et):
handle = ctypes.c_int(handle)<EOL>descr = stypes.toDoubleVector(descr)<EOL>et = ctypes.c_double(et)<EOL>ref = ctypes.c_int()<EOL>state = stypes.emptyDoubleVector(<NUM_LIT:6>)<EOL>center = ctypes.c_int()<EOL>libspice.spkpvn_c(handle, descr, et, ctypes.byref(ref), state,<EOL>ctypes.byref(center))<EOL>return ref.value, stypes.cVectorToPython(state), center.value<EOL>
For a specified SPK segment and time, return the state (position and
velocity) of the segment's target body relative to its center of
motion.

http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/spkpvn_c.html

:param handle: File handle.
:type handle: int
:param descr: Segment descriptor.
:type descr: 5-Element Array of floats
:param et: Evaluation epoch.
:type et: float
:return:
        Segment reference frame ID code,
        Output state vector,
        Center of state.
:rtype: tuple