code: def get_OPinv_matvec(A, M, sigma, hermitian=False, tol=0):
      if sigma == 0:
          return get_inv_matvec(A, hermitian=hermitian, tol=tol)
  
      if M is None:
          # M is the identity matrix
          if isdense(A):
              if (
                  np.issubdtype(A.dtype, np.complexfloating)
                  or np.imag(sigma) == 0
              ):
                  A = np.copy(A)
              else:
                  A = A + 0j
              A.flat[:: A.shape[1] + 1] -= sigma
              return LuInv(A).matvec
          elif issparse(A) or is_pydata_spmatrix(A):
              A = A - sigma * eye(A.shape[0])
              A = _fast_spmatrix_to_csc(A, hermitian=hermitian)
              return SpLuInv(A).matvec
          else:
              return IterOpInv(
                  _aslinearoperator_with_dtype(A), M, sigma, tol=tol
              ).matvec
      else:
          if (
              not isdense(A)
              and not issparse(A)
              and not is_pydata_spmatrix(A)
          ) or (
              not isdense(M)
              and not issparse(M)
              and not is_pydata_spmatrix(A)
          ):
              return IterOpInv(
                  _aslinearoperator_with_dtype(A),
                  _aslinearoperator_with_dtype(M),
                  sigma,
                  tol=tol,
              ).matvec
          elif isdense(A) or isdense(M):
              return LuInv(A - sigma * M).matvec
          else:
              OP = A - sigma * M
              OP = _fast_spmatrix_to_csc(OP, hermitian=hermitian)
              return SpLuInv(OP).matvec
  
imports: import numpy
  import warnings
  from scipy.sparse.linalg._interface import aslinearoperator, LinearOperator
  from scipy.sparse import eye, issparse
  from scipy.linalg import eig, eigh, lu_factor, lu_solve
  from scipy.sparse._sputils import isdense, is_pydata_spmatrix
  from scipy.sparse.linalg import gmres, splu
  from scipy._lib._util import _aligned_zeros
  from scipy._lib._threadsafety import ReentrancyLock
  from .None import _arpack
label_desc: Use image node_id 6 for calling a global function with example usage: get_OPinv_matvec(A, M, sigma, hermitian, tol) and returns: get_inv_matvec, LuInv, IterOpInv, SpLuInv, IterOpInv, LuInv, SpLuInv