code: def dtype(self, dtype):
      self._data = ivy.astype(self._data, dtype)
      self._dtype = self._data.dtype
  
file_path: ivy/ivy/functional/frontends/numpy/matrix/methods.py
imports: import ivy
  from ivy.functional.frontends.numpy import argmax, any, ndarray
label_desc: Use image node_id 13 for calling the matrix obj's underlying member method code with example usage: obj.dtype(dtype) without return types