code: def _validate_vector(u, dtype=None):
      # this is taken from scipy.spatial.distance. Internal function, so
      # redefining here.
  
      u = np.asarray(u, dtype=dtype).squeeze()
      # Ensure values such as u=1 and u=[1] still return 1-D arrays.
      u = np.atleast_1d(u)
      if u.ndim > 1:
          raise ValueError("Input vector should be 1-D.")
      return u
  
imports: from __future__ import absolute_import, division, unicode_literals
  import math
  from math import cos, sin
  import random
  import warnings
  import numpy
  from numpy.linalg import inv
  import scipy.linalg
  import scipy.sparse
  import scipy.sparse.linalg
  from scipy.stats import norm, multivariate_normal
label_desc: Use image node_id 1 for calling a global function with example usage: _validate_vector(u, dtype) and returns: u