docstr: Returns the density of each input.
docstr_tok: ["Returns","the","density","of","each","input","."]
code: def density(self, X: np.ndarray) -> np.ndarray:
      """Returns the density of each input."""
      raise NotImplementedError
  
imports: from abc import ABC, abstractmethod
  import numpy
label_desc: Use image node_id 2 for calling the DensityEstimator obj's underlying member method code with example usage: obj.density(X) without return types