message: Rewrote the tests to use the final output instead of the intermediate weights and geometry values.
diff: @@ -547,7 +547,7 @@ class MBTR(Descriptor):
  mbtr = {}
  if self.k1 is not None:
  cell_indices = np.zeros((len(system), 3), dtype=int)
  - mbtr["k1"] = self.get_k1(system, cell_indices)
  + mbtr["k1"] = self._get_k1(system, cell_indices)
  if self.k2 is not None:
  # If needed, create the extended system
  system_k2 = system
  @@ -555,7 +555,7 @@ class MBTR(Descriptor):
  system_k2, cell_indices = self.create_extended_system(system, 2)
  else:
  cell_indices = np.zeros((len(system), 3), dtype=int)
  - mbtr["k2"] = self.get_k2(system_k2, cell_indices)
  + mbtr["k2"] = self._get_k2(system_k2, cell_indices)
  # Free memory
  system_k2 = None
  @@ -567,7 +567,7 @@ class MBTR(Descriptor):
  system_k3, cell_indices = self.create_extended_system(system, 3)
  else:
  cell_indices = np.zeros((len(system), 3), dtype=int)
  - mbtr["k3"] = self.get_k3(system_k3, cell_indices)
  + mbtr["k3"] = self._get_k3(system_k3, cell_indices)
  # Free memory
  system_k3 = None
  @@ -878,7 +878,7 @@ class MBTR(Descriptor):
  return extended_system, cell_indices
  - def get_k1(self, system, cell_indices):
  + def _get_k1(self, system, cell_indices):
  """Calculates the second order terms where the scalar mapping is the
  inverse distance between atoms.
  @@ -936,7 +936,7 @@ class MBTR(Descriptor):
  return k1
  - def get_k2(self, system, cell_indices):
  + def _get_k2(self, system, cell_indices):
  """Calculates the second order terms where the scalar mapping is the
  inverse distance between atoms.
  @@ -1032,7 +1032,7 @@ class MBTR(Descriptor):
  return k2
  - def get_k3(self, system, cell_indices):
  + def _get_k3(self, system, cell_indices):
  """Calculates the third order terms.
  Returns:
  