code: def render(self, r):
      reader = {
          "name": "MatrixBGENReader",
          "files": self.path,
          "sampleFile": self.sample_file,
          "indexFileMap": self.index_file_map,
          "nPartitions": self.n_partitions,
          "blockSizeInMB": self.block_size,
          "includedVariants": self.included_variants,
      }
      return escape_str(json.dumps(reader))
  
imports: import abc
  import json
  from .utils import make_filter_and_replace, impute_type_of_partition_interval_array
  from ..expr.types import HailType, tfloat32, tfloat64
  from ..genetics.reference_genome import reference_genome_type
  from ..typecheck import typecheck_method, sequenceof, nullable, enumeration, anytype, oneof, dictof, sized_tupleof
  from ..utils import wrap_to_list
  from ..utils.misc import escape_str
label_desc: Use image node_id 2 for calling the MatrixBGENReader obj's underlying member method code with example usage: obj.render(r) and returns: escape_str