class_docstr: Test renderer implemented using Matplotlib.
  
  No whitespace around plots and no spines/ticks displayed.
  Uses Agg backend, so can only save to file/buffer, cannot call ``show()``.
code: def __init__(
      self,
      nrows: int = 1,
      ncols: int = 1,
      figsize: tuple[float, float] = (9, 9),
  ) -> None:
      gridspec = {
          "left": 0.01,
          "right": 0.99,
          "top": 0.99,
          "bottom": 0.01,
          "wspace": 0.01,
          "hspace": 0.01,
      }
      super().__init__(
          nrows,
          ncols,
          figsize,
          show_frame=True,
          backend="Agg",
          gridspec_kw=gridspec,
      )
  
      for ax in self._axes:
          ax.set_xmargin(0.0)
          ax.set_ymargin(0.0)
          ax.set_xticks([])
          ax.set_yticks([])
  
      self._want_tight = False
  
imports: from __future__ import annotations
  from collections.abc import Sequence
  import io
  from typing import TYPE_CHECKING, Any, cast
  import matplotlib.collections
  import matplotlib.pyplot
  import numpy
  from contourpy import FillType, LineType
  from contourpy.convert import convert_filled, convert_lines
  from contourpy.enum_util import as_fill_type, as_line_type
  from contourpy.util.mpl_util import filled_to_mpl_paths, lines_to_mpl_paths
  from contourpy.util.renderer import Renderer
label_desc: Use image node_id 1 to create a new MplTestRenderer object from inherited base classes: MplRenderer with example: obj = MplTestRenderer(nrows, ncols, figsize)