diff --git a/openmc/plots.py b/openmc/plots.py
index c6af5eea1..67b65440a 100644
--- a/openmc/plots.py
+++ b/openmc/plots.py
@@ -270,7 +270,7 @@ class PlotBase(IDManagerMixin):
         Name of the plot
     pixels : Iterable of int
         Number of pixels to use in each direction
-    filename :
+    filename : str
         Path to write the plot to
     color_by : {'cell', 'material'}
         Indicate whether the plot should be colored by cell or by material
@@ -279,7 +279,7 @@ class PlotBase(IDManagerMixin):
     mask_components : Iterable of openmc.Cell or openmc.Material or int
         The cells or materials (or corresponding IDs) to mask
     mask_background : Iterable of int or str
-        Color to apply to all cells/materials not listed in mask_components
+        Color to apply to all cells/materials listed in mask_components
     show_overlaps : bool
         Indicate whether or not overlapping regions are shown
     overlap_color : Iterable of int or str
@@ -515,7 +515,7 @@ class PlotBase(IDManagerMixin):
 
 
 class Plot(PlotBase):
-    '''Definition of a finite region of space to be plotted.
+    """Definition of a finite region of space to be plotted.
 
     OpenMC is capable of generating two-dimensional slice plots, or
     three-dimensional voxel or projection plots. Colors that are used in plots can be given as
@@ -531,6 +531,33 @@ class Plot(PlotBase):
 
     Attributes
     ----------
+    id : int
+        Unique identifier
+    name : str
+        Name of the plot
+    pixels : Iterable of int
+        Number of pixels to use in each direction
+    filename : str
+        Path to write the plot to
+    color_by : {'cell', 'material'}
+        Indicate whether the plot should be colored by cell or by material
+    background : Iterable of int or str
+        Color of the background
+    mask_components : Iterable of openmc.Cell or openmc.Material or int
+        The cells or materials (or corresponding IDs) to mask
+    mask_background : Iterable of int or str
+        Color to apply to all cells/materials listed in mask_components
+    show_overlaps : bool
+        Indicate whether or not overlapping regions are shown
+    overlap_color : Iterable of int or str
+        Color to apply to overlapping regions
+    colors : dict
+        Dictionary indicating that certain cells/materials should be
+        displayed with a particular color. The keys can be of type
+        :class:`~openmc.Cell`, :class:`~openmc.Material`, or int (ID for a
+        cell/material).
+    level : int
+        Universe depth to plot at
     width : Iterable of float
         Width of the plot in each basis direction
     origin : tuple or list of ndarray
@@ -543,7 +570,7 @@ class Plot(PlotBase):
         Dictionary defining type, id, linewidth and color of a mesh to be
         plotted on top of a plot
 
-    '''
+    """
 
     def __init__(self, plot_id=None, name=''):
         super().__init__(plot_id, name)
diff --git a/openmc/plotter.py b/openmc/plotter.py
index d8e06e4fe..193ba9cbe 100644
--- a/openmc/plotter.py
+++ b/openmc/plotter.py
@@ -59,7 +59,7 @@ def _get_legend_label(this, type):
     """Gets a label for the element or nuclide or material and reaction plotted"""
     if isinstance(this, str):
         return f'{this} {type}'
-    elif this.name is '':
+    elif this.name == '':
         return f'Material {this.id} {type}'
     else:
         return f'{this.name} {type}'
diff --git a/src/plot.cpp b/src/plot.cpp
index 1f629e901..b4c8cad16 100644
--- a/src/plot.cpp
+++ b/src/plot.cpp
@@ -5,8 +5,8 @@
 #include <fstream>
 #include <sstream>
 
-#include "xtensor/xview.hpp"
 #include "xtensor/xmanipulation.hpp"
+#include "xtensor/xview.hpp"
 #include <fmt/core.h>
 #include <fmt/ostream.h>
 #ifdef USE_LIBPNG
@@ -14,6 +14,7 @@
 #endif
 
 #include "openmc/constants.h"
+#include "openmc/container_util.h"
 #include "openmc/dagmc.h"
 #include "openmc/error.h"
 #include "openmc/file_utils.h"
@@ -647,7 +648,7 @@ void PlottableInterface::set_mask(pugi::xml_node plot_node)
 
       // Alter colors based on mask information
       for (int j = 0; j < colors_.size(); j++) {
-        if (std::find(iarray.begin(), iarray.end(), j) == iarray.end()) {
+        if (contains(iarray, j)) {
           if (check_for_node(mask_node, "background")) {
             vector<int> bg_rgb = get_node_array<int>(mask_node, "background");
             colors_[j] = bg_rgb;
@@ -1306,12 +1307,15 @@ void ProjectionPlot::create_output() const
             bool inside_cell = false;
 
             int32_t i_surface = std::abs(p.surface()) - 1;
-            if (i_surface > 0 && model::surfaces[i_surface]->geom_type_ == GeometryType::DAG) {
+            if (i_surface > 0 &&
+                model::surfaces[i_surface]->geom_type_ == GeometryType::DAG) {
 #ifdef DAGMC
-              int32_t i_cell = next_cell(i_surface, p.cell_last(p.n_coord() - 1), p.lowest_coord().universe);
+              int32_t i_cell = next_cell(i_surface,
+                p.cell_last(p.n_coord() - 1), p.lowest_coord().universe);
               inside_cell = i_cell >= 0;
 #else
-              fatal_error("Not compiled for DAGMC, but somehow you have a DAGCell!");
+              fatal_error(
+                "Not compiled for DAGMC, but somehow you have a DAGCell!");
 #endif
             } else {
               inside_cell = exhaustive_find_cell(p);
diff --git a/tests/regression_tests/plot/results_true.dat b/tests/regression_tests/plot/results_true.dat
index 9174202fb..1be60ad4f 100644
--- a/tests/regression_tests/plot/results_true.dat
+++ b/tests/regression_tests/plot/results_true.dat
@@ -1 +1 @@
-f85c20735a0c08525fe48b19a8e075c074539ee6c8860268fa0cb515d842496b7086e5b94305ef78dcf2106bb193abdf438259ac8ff1d0245a2782eb6f5af873
\ No newline at end of file
+6385d2969ed54d47a09f75112595fc034a16f551346c92d87ed9e7841881baaee8e56190c347e97c3f919ef677bb5b858960d60fe985a00e2848a3bfbef7a12b
\ No newline at end of file
diff --git a/tests/regression_tests/plot_overlaps/results_true.dat b/tests/regression_tests/plot_overlaps/results_true.dat
index cb04daaa4..93ee6769f 100644
--- a/tests/regression_tests/plot_overlaps/results_true.dat
+++ b/tests/regression_tests/plot_overlaps/results_true.dat
@@ -1 +1 @@
-926065ceb2a9b8292fe6270317c38c4373473cfea19d2a8392a32e5ece8e314c04b9f032921d987bd195ae4b6f674d359b0e38302e6ae4c93b4ac9573a384ac6
\ No newline at end of file
+125ce40fbff3e02e7f5f36a92a2e37abce9407154c825b6617242a4685dfc33c63041145b1f3114334338fbb86188331195ddc319ffce58fab2943d8e60f6da3
\ No newline at end of file
diff --git a/tests/regression_tests/plot_projections/results_true.dat b/tests/regression_tests/plot_projections/results_true.dat
index a2cb57b1e..1a67da300 100644
--- a/tests/regression_tests/plot_projections/results_true.dat
+++ b/tests/regression_tests/plot_projections/results_true.dat
@@ -1 +1 @@
-6448093f8acaa2af02452ec1b29461ffaf89628bb002cc8873a3a6831fe5d613645a197033597e5a064896388f19d0782f05e78ce474354ae2a76c35ff4551d7
\ No newline at end of file
+24fb0f41ee018ea086962dbd6bcd0b536d11d4b34644bfef4f0e74f8b462fe41a84af39c7ff79046d5d7cfe209084eac54712fa0ec01038e97eb43df1abd0334
\ No newline at end of file