<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def soma_surface_area(nrn, neurite_type=NeuriteType.soma):
    '''Get the surface area of a neuron's soma.

    Note:
        The surface area is calculated by assuming the soma is spherical.
    '''
    assert neurite_type == NeuriteType.soma, 'Neurite type must be soma'
    return 4 * math.pi * nrn.soma.radius ** 2