code: def clean0(matrix):
      """
      Erase columns of zeros: can save some time in pseudoinverse.
  
      Parameters
      ----------
      matrix : ndarray
          The array to clean.
  
      Returns
      -------
      ndarray
          The cleaned array.
      """
      colsum = np.add.reduce(matrix**2, 0)
      val = [matrix[:, i] for i in np.flatnonzero(colsum)]
      return np.array(np.transpose(val))
  
imports: import numpy
  import pandas
  import scipy.linalg
  from statsmodels.tools.data import _is_using_pandas
  from statsmodels.tools.validation import array_like
label_desc: Use image node_id 10 for calling a global function with example usage: clean0(matrix) and returns: np