code: def naked(x):
      if hasattr(x, "spmatrix"):
          return x.spmatrix
      if not is_sparse_or_dense(x):
          raise TypeError("only sparse matrix or ndarray accepted")
      return x
  
file_path: mars/mars/lib/sparse/core.py
imports: import numpy
  from ...utils import lazy_import
label_desc: Use image node_id 7 for calling a global function with example usage: naked(x) and returns: x, x