docstr: Defines the starting values for the parameters
  The linear regression gives us reasonable starting values for the constant
  d and the variance of the epsilon error
code: def start_params(self):
      """
      Defines the starting values for the parameters
      The linear regression gives us reasonable starting values for the constant
      d and the variance of the epsilon error
      """
      exog = sm.add_constant(self.exog)
      res = sm.OLS(self.endog, exog).fit()
      params = np.r_[res.params[0], res.scale, 0.001, 0.001]
      return params
  
imports: from collections import OrderedDict
  import matplotlib.pyplot
  import numpy
  import pandas
  import statsmodels.api
  import pymc3
  import theano
  import theano.tensor
label_desc: Use image node_id 3 for calling the TVRegression obj's underlying member method code with example usage: obj.start_params() and returns: params