ImportError: cannot import name check_array from sklearn.utils.validation

When I import the function `check_array` from module `sklearn.utils.validation`, it got an Import Error (`ImportError: cannot import name check_array`). The tab completion got `check_arrays`, but I'm wondering there only exists a function called `check_array` in `validation.py` ( source code on Github). Besides, the spectral clustering algorithm implemented in scikit-learn/sklearn/cluster/spectral.py also used `from ..utils.validation import check_array`, not `check_arrays`. I'm quite confused about this, and my scikit-learn version is `'0.15.0b1'`. Hope somebody gives me a clue. sample code ``` import numpy as np from sklearn.utils.validation import check_array def my_fit_affinity(X, affinity_type, n_neighbors, **kernel_params): """ Create an affinity matrix for X using the selected affinity type """ X = check_array(X, accept_sparse = ['csr', 'csc', 'coo']) .... return affinity_matrix_ ```