message: Allow specifying range for uniform predefined grid for compatibility with old class
diff: @@ -359,8 +359,8 @@ class BettiCurve2(BaseEstimator, TransformerMixin):
  Parameters
  ----------
  - predefined_grid: 1d array or None, default=None
  - Predefined filtration grid points at which to compute the Betti curves. Must be strictly ordered. Infinities are OK. If None (default), a grid will be computed that captures all changes in Betti numbers in the provided data.
  + predefined_grid: 1d array, triple or None, default=None
  + Predefined filtration grid points at which to compute the Betti curves. Must be strictly ordered. Infinities are OK. If a triple of the form (l, u, n), the grid will be uniform from l to u in n steps. If None (default), a grid will be computed that captures all changes in Betti numbers in the provided data.
  Attributes
  ----------
  @@ -382,6 +382,12 @@ class BettiCurve2(BaseEstimator, TransformerMixin):
  """
  def __init__(self, predefined_grid = None):
  + if isinstance(predefined_grid, tuple):
  + if len(predefined_grid) != 3:
  + raise ValueError("Expected array, None or triple.")
  +
  + self.predefined_grid = np.linspace(predefined_grid[0], predefined_grid[1], predefined_grid[2])
  + else:
  self.predefined_grid = predefined_grid
  