@spiceErrorCheck<EOL>def qdq2av(q, dq):
q = stypes.toDoubleVector(q)<EOL>dq = stypes.toDoubleVector(dq)<EOL>vout = stypes.emptyDoubleVector(<NUM_LIT:3>)<EOL>libspice.qdq2av_c(q, dq, vout)<EOL>return stypes.cVectorToPython(vout)<EOL>
Derive angular velocity from a unit quaternion and its derivative
with respect to time.

http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/qdq2av_c.html

:param q: Unit SPICE quaternion.
:type q: 4-Element Array of floats
:param dq: Derivative of q with respect to time
:type dq: 4-Element Array of floats
:return: Angular velocity defined by q and dq.
:rtype: 3-Element Array of floats