code: def rptree_leaf_array(rp_forest):
      if len(rp_forest) > 0:
          return np.vstack(rptree_leaf_array_parallel(rp_forest))
      else:
          return np.array([[-1]])
  
imports: from warnings import warn
  import locale
  import numpy
  import numba
  import scipy.sparse
  from pynndescent.sparse import sparse_mul, sparse_diff, sparse_sum, arr_intersect, sparse_dot_product
  from pynndescent.utils import tau_rand_int, norm
  import joblib
  from collections import namedtuple
label_desc: Use image node_id 18 for calling a global function with example usage: rptree_leaf_array(rp_forest) and returns: np, np