code: def _first_block(dask_object):
      
      if isinstance(dask_object, da.Array):
          if dask_object.ndim > 1 and dask_object.numblocks[-1] != 1:
              raise NotImplementedError(
                  "IID estimators require that the array "
                  "blocked only along the first axis. "
                  "Rechunk your array before fitting."
              )
          shape = (dask_object.chunks[0][0],)
          if dask_object.ndim > 1:
              shape = shape + (dask_object.chunks[1][0],)
  
          return da.from_delayed(
              dask_object.to_delayed().flatten()[0], shape, dask_object.dtype
          )
  
      if isinstance(dask_object, dd._Frame):
          return dask_object.get_partition(0)
  
      else:
          return dask_object
docs: Extract the first block / partition from a dask object