class_docstr: Categorical Distribution 
class_docstr_tok: ["Categorical","Distribution"]
docstr: Returns pmf of distribution at x. 
code: def pmf(self, i):
      """Returns pmf of distribution at x."""
      if i < 0 or i >= self.k:
          return 0
      return np.asscalar(self.p[i])
  
imports: from __future__ import absolute_import
  import numpy
  from .distribution import Discrete
  from ..exd import domains
label_desc: Use image node_id 2 for calling the Categorical obj's underlying member method code with example usage: obj.pmf(i) and returns: np, int