def spherical_harmonic(theta, phi, m=0, n=0):
    return sph_harm(m, n, phi, theta).real
Returns the number of items in the data store.
dataset/ETHPy150Open python-acoustics/python-acoustics/acoustics/directivity.py/spherical_harmonic--crossover with--dataset/ETHPy150Open ntoll/p4p2p/p4p2p/dht/storage.py/DictDataStore.__len__