code: def read_int16_matrix(fid, rows, cols):
      """Read 16bit integer matrix from bti file."""
      return _unpack_matrix(
          fid,
          rows,
          cols,
          dtype=">i2",
          out_dtype=np.int32,
      )
  
imports: import numpy
  from ..._fiff.utils import read_str
label_desc: Use image node_id 15 for calling a global function with example usage: read_int16_matrix(fid, rows, cols) and returns: _unpack_matrix