new_contents: import numpy as np
  from menpofit.math.correlationfilter import mccf, imccf
  
  
  # TODO: document me!
  class IncrementalCorrelationFilterThinWrapper(object):
      r"""
      """
      def __init__(self, cf_callable=mccf, icf_callable=imccf):
          self.cf_callable = cf_callable
          self.icf_callable = icf_callable
  
      def increment(self, A, B, n_x, Z, t):
          r"""
          """
          # Turn list of X into ndarray
          if isinstance(Z, list):
              Z = np.asarray(Z)
          return self.icf_callable(A, B, n_x, Z, t)
  
      def train(self, X, t):
          r"""
          """
          # Turn list of X into ndarray
          if isinstance(X, list):
              X = np.asarray(X)
          # Return linear svm filter and bias
          return self.cf_callable(X, t)
  
subject: Add dummy wrapper for correlation filters