code: def _mul_multivector(self, other):
      # matrix * multivector
      result_shape = (self.shape[0], other.shape[1])
      result_dtype = upcast(self.dtype, other.dtype)
      result = np.zeros(result_shape, dtype=result_dtype)
      for (i, j), v in self.items():
          result[i, :] += v * other[j, :]
      return result
  
imports: import itertools
  import numpy
  from ._matrix import spmatrix
  from ._base import _spbase, sparray, issparse
  from ._index import IndexMixin
  from ._sputils import isdense, getdtype, isshape, isintlike, isscalarlike, upcast, upcast_scalar, check_shape
label_desc: Use image node_id 33 for calling the _dok_base obj's underlying member method code with example usage: obj._mul_multivector(other) and returns: result