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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 A_cylinder(D, L):
    r'''Returns the surface area of a cylinder.

    .. math::
        A = \pi D L + 2\cdot \frac{\pi D^2}{4}

    Parameters
    ----------
    D : float
        Diameter of the cylinder, [m]
    L : float
        Length of the cylinder, [m]

    Returns
    -------
    A : float
        Surface area [m]

    Examples
    --------
    >>> A_cylinder(0.01, .1)
    0.0032986722862692833
    '''
    cap = pi*D**2/4*2
    side = pi*D*L
    A = cap + side
    return A