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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def vlcom(a, v1, b, v2):
 """ Compute a vector linear combination of two double precision, 3-dimensional vectors. http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/vlcom_c.html :param a: Coefficient of v1 :type a: float :param v1: Vector in 3-space :type v1: 3-Element Array of floats :param b: Coefficient of v2 :type b: float :param v2: Vector in 3-space :type v2: 3-Element Array of floats :return: Linear Vector Combination a*v1 + b*v2. :rtype: 3-Element Array of floats """

    v1 = stypes.toDoubleVector(v1)
    v2 = stypes.toDoubleVector(v2)
    sumv = stypes.emptyDoubleVector(3)
    a = ctypes.c_double(a)
    b = ctypes.c_double(b)
    libspice.vlcom_c(a, v1, b, v2, sumv)
    return stypes.cVectorToPython(sumv)