class_docstr: Implementation of the random-dot motion environment 
class_docstr_tok: ["Implementation","of","the","random-dot","motion","environment"]
code: def _generate_dot_dist(self):
      _stateidx = self.direction_names.index(self._dot_dir)
      if self._dot_dir == "null":
          self.dot_dist = utils.onehot(_stateidx, self.n_states)
      else:
          dot_dist = np.zeros(self.n_states)
          dot_dist[1:] = maths.softmax(
              self._p
              * utils.onehot(
                  _stateidx - 1, len(self.direction_names) - 1
              )
          )
          self.dot_dist = dot_dist
  
      return self.dot_dist
  
imports: from pymdp.envs import Env
  from pymdp import utils, maths
  import numpy
  from itertools import permutations, product
label_desc: Use image node_id 4 for calling the RandomDotMotion obj's underlying member method code with example usage: obj._generate_dot_dist() and returns: self