code: def density_at_zero(y, mu, p, phi):
      return np.exp(-(mu ** (2 - p)) / (phi * (2 - p)))
  
file_path: statsmodels/statsmodels/genmod/_tweedie_compound_poisson.py
imports: import numpy
  from scipy._lib._util import _lazywhere
  from scipy.special import gammaln
label_desc: Use image node_id 7 for calling a global function with example usage: density_at_zero(y, mu, p, phi) and returns: np