class_docstr: An example transformer that returns the element-wise square root.
  
  For more information regarding how to build your own transformer, read more
  in the :ref:`User Guide <user_guide>`.
  
  Parameters
  ----------
  demo_param : str, default='demo'
      A parameter used for demonstation of how to pass and store paramters.
  
  Attributes
  ----------
  n_features_ : int
      The number of features of the data passed to :meth:`fit`.
code: def __init__(self, demo_param="demo"):
      self.demo_param = demo_param
  
imports: from sklearn.base import BaseEstimator, ClassifierMixin, TransformerMixin
  from sklearn.metrics import euclidean_distances
  from sklearn.utils.multiclass import unique_labels
  from sklearn.utils.validation import check_array, check_is_fitted, check_X_y
  import geomstats.backend
label_desc: Use image node_id 1 to create a new TemplateTransformer object from inherited base classes: BaseEstimator, TransformerMixin with example: obj = TemplateTransformer(demo_param)