Add missing file

Signed-off-by: Steven Wright <steven.wright@york.ac.uk>

p3/plot/backend/__init__.py

@@ -13,7 +13,8 @@
 __all__ = [
     "Plot",
     "CascadePlot",
-    "CascadePGFPlot" "NavChart",
+    "CascadePGFPlot",
+    "NavChart",
 ]
 
 

p3/plot/backend/pgfplots.py

@@ -0,0 +1,28 @@
+# Copyright (c) 2022-2023 Intel Corporation
+# SPDX-License-Identifier: MIT
+"""
+Contains objects for interacting with plots produced using the
+:py:mod:`pgfplots` backend.
+"""
+
+from . import CascadePGFPlot
+
+
+class CascadePGFPlot(CascadePGFPlot):
+    """
+    Cascade plot object for :py:mod:`pgfplots`.
+    """
+
+    def __init__(self, stream):
+        super().__init__("pgfplots")
+        self.stream = stream
+
+    def save(self, filename):
+        """
+        Save the plot to the specified file.
+
+        Parameters
+        ----------
+        filename: string
+        """
+        self.stream.dump(filename)