code: def spsolve(A, b):
      """Solves a sparse linear system ``A x = b``
  
      Args:
          A (cupyx.scipy.sparse.spmatrix):
              Sparse matrix with dimension ``(M, M)``.
          b (cupy.ndarray):
              Dense vector or matrix with dimension ``(M)`` or ``(M, N)``.
  
      Returns:
          cupy.ndarray:
              Solution to the system ``A x = b``.
      """
      import cupyx.cusolver
  
      if not cupyx.cusolver.check_availability("csrlsvqr"):
          raise NotImplementedError
      if not sparse.isspmatrix(A):
          raise TypeError("A must be cupyx.scipy.sparse.spmatrix")
      if not isinstance(b, cupy.ndarray):
          raise TypeError("b must be cupy.ndarray")
      if A.shape[0] != A.shape[1]:
          raise ValueError(
              "A must be a square matrix (A.shape: {})".format(A.shape)
          )
      if not (b.ndim == 1 or b.ndim == 2):
          raise ValueError(
              "Invalid b.shape (b.shape: {})".format(b.shape)
          )
      if A.shape[0] != b.shape[0]:
          raise ValueError(
              "matrix dimension mismatch (A.shape: {}, b.shape: {})".format(
                  A.shape, b.shape
              )
          )
  
      if not sparse.isspmatrix_csr(A):
          warnings.warn(
              "CSR format is required. Converting to CSR format.",
              sparse.SparseEfficiencyWarning,
          )
          A = A.tocsr()
      A.sum_duplicates()
      b = b.astype(A.dtype, copy=False)
  
      if b.ndim > 1:
          res = cupy.empty_like(b)
          for j in range(res.shape[1]):
              res[:, j] = cupyx.cusolver.csrlsvqr(A, b[:, j])
          res = cupy.asarray(res, order="F")
          return res
      else:
          return cupyx.cusolver.csrlsvqr(A, b)
  
imports: import numpy
  import cupy
  from cupy import cublas
  from cupy.cuda import device
  from cupy.cuda import runtime
  from cupy.linalg import _util
  from cupyx.scipy import sparse
  from cupyx.scipy.sparse.linalg import _interface
  from cupyx.scipy.sparse.linalg._iterative import _make_system
  import warnings
label_desc: Use image node_id 5 for calling a global function with example usage: spsolve(A, b) and returns: res, cupyx