def Pn(x):
    """Calculate Legendre polyomials P0 to P28 and returns them
    in a dictionary ``Pn``.

    :param float x:     argument to calculate Legendre polynomials
    :return Pn:         dictionary which contains order of Legendre polynomials
                        (from 0 to 28) as keys and the corresponding evaluation
                        of Legendre polynomials as values.
    :rtype:             dict

    """
    Pn = {}
    Pn['0'] = P0(x)
    Pn['1'] = P1(x)
    Pn['2'] = P2(x)
    Pn['3'] = P3(x)
    Pn['4'] = P4(x)
    Pn['5'] = P5(x)
    Pn['6'] = P6(x)
    Pn['8'] = P8(x)
    Pn['10'] = P10(x)
    Pn['12'] = P12(x)
    Pn['14'] = P14(x)
    Pn['16'] = P16(x)
    Pn['18'] = P18(x)
    Pn['20'] = P20(x)
    Pn['22'] = P22(x)
    Pn['24'] = P24(x)
    Pn['26'] = P26(x)
    Pn['28'] = P28(x)
    return Pn
Calculate Legendre polyomials P0 to P28 and returns them
    in a dictionary ``Pn``.

    :param float x:     argument to calculate Legendre polynomials
    :return Pn:         dictionary which contains order of Legendre polynomials
                        (from 0 to 28) as keys and the corresponding evaluation
                        of Legendre polynomials as values.
    :rtype:             dict