code: def matvec(A, b):
      if b.ndim == 1:
          return _np.matmul(A, b)
      if A.ndim == 2:
          return _np.matmul(A, b.T).T
      return _np.einsum("...ij,...j->...i", A, b)
  
imports: from ._dispatch import BACKEND_NAME, _common
  from ._dispatch import numpy
label_desc: Use image node_id 26 for calling a global function with example usage: matvec(A, b) and returns: _np, _np, _np