class_docstr: Base class for structure estimators in pgmpy.
  
  Parameters
  ----------
  data: pandas DataFrame object
      dataframe object where each column represents one variable.
      (If some values in the data are missing the data cells should be set to `numpy.NaN`.
      Note that pandas converts each column containing `numpy.NaN`s to dtype `float`.)
  
  state_names: dict (optional)
      A dict indicating, for each variable, the discrete set of states (or values)
      that the variable can take. If unspecified, the observed values in the data set
      are taken to be the only possible states.
code: def estimate(self):
      pass
  
file_path: pgmpy/pgmpy/estimators/base.py
imports: from collections import OrderedDict
  import pandas
label_desc: Use image node_id 2 for calling the StructureEstimator obj's underlying member method code with example usage: obj.estimate() without return types