code: def __init__(self, n_rows, n_cols, n_partitions):
      self.n_rows = n_rows
      self.n_cols = n_cols
      self.n_partitions = n_partitions
  
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 1 to create a new MatrixRangeReader object from inherited base classes: MatrixReader with example: obj = MatrixRangeReader(n_rows, n_cols, n_partitions)