code: def _makeMatMat(m):
      if m is None:
          return None
      elif callable(m):
          return lambda v: m(v)
      else:
          return lambda v: m @ v
  
file_path: scipy/scipy/sparse/linalg/_eigen/lobpcg/lobpcg.py
imports: import warnings
  import numpy
  from scipy.linalg import inv, eigh, cho_factor, cho_solve, cholesky, LinAlgError
  from scipy.sparse.linalg import LinearOperator
  from scipy.sparse import issparse
label_desc: Use image node_id 3 for calling a global function with example usage: _makeMatMat(m) and returns: None, function, function