def Pnprime(x):
    """Calculates first derivatives of Legendre polynomials and returns them
    in a dictionary ``Pnprime``.

    :param float x:     argument to calculate first derivate of Legendre polynomials
    :return Pn:         dictionary which contains order of Legendre polynomials
                        (from 0 to 4 and even numbers until 14) as keys and
                        the corresponding evaluation of first derivative of
                        Legendre polynomials as values.
    :rtype:             dict

    """
    Pnprime = {}
    Pnprime['0'] = 0
    Pnprime['1'] = P1prime(x)
    Pnprime['2'] = P2prime(x)
    Pnprime['3'] = P3prime(x)
    Pnprime['4'] = P4prime(x)
    Pnprime['6'] = P6prime(x)
    Pnprime['8'] = P8prime(x)
    Pnprime['10'] = P10prime(x)
    Pnprime['12'] = P12prime(x)
    Pnprime['14'] = P14prime(x)
    return Pnprime