class_docstr: Semiparametric partially linear model, ``Y = Xb + g(Z) + e``.
  
  Parameters
  ----------
  endog : array_like
      The dependent variable
  exog : array_like
      The linear component in the regression
  exog_nonparametric : array_like
      The nonparametric component in the regression
  var_type : str
      The type of the variables in the nonparametric component;
  
          - c: continuous
          - o: ordered
          - u: unordered
  
  k_linear : int
      The number of variables that comprise the linear component.
  
  Attributes
  ----------
  bw : array_like
      Bandwidths for the nonparametric component exog_nonparametric
  b : array_like
      Coefficients in the linear component
  nobs : int
      The number of observations.
  k_linear : int
      The number of variables that comprise the linear component.
  
  Methods
  -------
  fit
      Returns the fitted mean and marginal effects dy/dz
  
  Notes
  -----
  This model uses only the local constant regression estimator
  
  References
  ----------
  See chapter on Semiparametric Models in [1]
docstr: Computes the (beta) coefficients and the bandwidths.
  
  Minimizes ``cv_loo`` with respect to ``b`` and ``bw``.
docstr_tok: ["Computes","the","(","beta",")","coefficients","and","the","bandwidths",".","Minimizes","``","cv_loo","``","with","respect","to","``","b","``","and","``","bw","``","."]
code: def _est_b_bw(self):
      """
      Computes the (beta) coefficients and the bandwidths.
  
      Minimizes ``cv_loo`` with respect to ``b`` and ``bw``.
      """
      params0 = np.random.uniform(size=(self.k_linear + self.K,))
      b_bw = optimize.fmin(self.cv_loo, params0, disp=0)
      b = b_bw[0 : self.k_linear]
      bw = b_bw[self.k_linear :]
      # bw = self._set_bw_bounds(np.asarray(bw))
      return b, bw
  
imports: import numpy
  from scipy import optimize
  from scipy.stats.mstats import mquantiles
  from statsmodels.nonparametric.api import KDEMultivariate, KernelReg
  from statsmodels.nonparametric._kernel_base import gpke, LeaveOneOut, _get_type_pos, _adjust_shape
label_desc: Use image node_id 2 for calling the SemiLinear obj's underlying member method code with example usage: obj._est_b_bw() and returns: b,  bw