code: def q2m(q):
      
      q = stypes.toDoubleVector(q)
      mout = stypes.emptyDoubleMatrix()
      libspice.q2m_c(q, mout)
      return stypes.cMatrixToNumpy(mout)
docs: Find the rotation matrix corresponding to a specified unit quaternion.
  
      http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/q2m_c.html
  
      :param q: A unit quaternion.
      :type q: 4-Element Array of floats
      :return: A rotation matrix corresponding to q
      :rtype: 3x3-Element Array of floats