'Evaluate the spline at points
Returns the interpolated value at ``(theta[i], phi[i]),
i=0,...,len(theta)-1``.
Parameters
theta, phi : array_like
Input coordinates. Standard Numpy broadcasting is obeyed.
dtheta : int, optional
Order of theta-derivative
.. versionadded:: 0.14.0
dphi : int, optional
Order of phi-derivative
.. versionadded:: 0.14.0'

def ev(self, theta, phi, dtheta=0, dphi=0):

    return self.__call__(theta, phi, dtheta=dtheta, dphi=dphi, grid=False)
