code: def astype(self, dtype, casting="unsafe", copy=True):
      dtype = np.dtype(dtype)
      if self.dtype != dtype:
          return self._with_data(
              self._deduped_data().astype(
                  dtype, casting=casting, copy=copy
              ),
              copy=copy,
          )
      elif copy:
          return self.copy()
      else:
          return self
  
imports: import numpy
  from .base import spmatrix, _ufuncs_with_fixed_point_at_zero
  from .sputils import isscalarlike, validateaxis, matrix
label_desc: Use image node_id 12 for calling the _data_matrix obj's underlying member method code with example usage: obj.astype(dtype, casting, copy) and returns: self, self, self