title: How to fix the error: could not find function "plot_grid"?
body: <p>I'm try to do the 
  <a href="https://www.kaggle.com/pavansubhasht/ibm-hr-analytics-attrition-dataset/downloads/WA_Fn-UseC_-HR-Employee-Attrition.csv/notebook" rel="nofollow noreferrer">Kaggle Project: Attrition in an Organization || Why Workers Quit?</a></p>
  
  <p>when I run a part of the code, which plot multiple graphs using R ggplot function "cowplot", </p>
  
  <pre><code>library(ggplot2)
  
  options(repr.plot.width=8, repr.plot.height=6)
  options(warn=-1)
  
  
  df &lt;- read.csv("C:/Users/Abdo Taha/Documents/WA_Fn-UseC_-HR-Employee-Attrition.csv")
  
  head(df)
  
  original_df &lt;- df
  
  
  attritions_number &lt;-
  df %&gt;% group_by(Attrition) %&gt;% summarise(Count = n()) %&gt;%
  ggplot(aes(x = Attrition, y = Count)) + geom_bar(stat = "identity", fill =
                                                    "orange", color = "grey40") + theme_bw() + coord_flip() +
  geom_text(
   aes(x = Attrition, y = 0.01, label = Count),
   hjust = -0.8,
   vjust = -1,
   size = 3,
   colour = "black",
   fontface = "bold",
   angle = 360
  ) + labs(title = "Employee Attrition (Amount)", x = "Employee Attrition", y =
            "Amount") + theme(plot.title = element_text(hjust = 0.5))
  
  attrition_percentage &lt;-
  df %&gt;% group_by(Attrition) %&gt;% summarise(Count = n()) %&gt;%
  mutate(pct = round(prop.table(Count), 2) * 100) %&gt;%
  ggplot(aes(x = Attrition, y = pct)) + geom_bar(stat = "identity", fill = "dodgerblue", color =
                                                  "grey40") +
  geom_text(
   aes(
     x = Attrition,
     y = 0.01,
     label = sprintf("%.2f%%", pct)
   ),
   hjust = 0.5,
   vjust = -3,
   size = 4,
   colour = "black",
   fontface = "bold"
  ) + theme_bw() + labs(x = "Employee Attrition", y = "Percentage") +
  labs(title = "Employee Attrition (%)") + theme(plot.title = element_text(hjust =
                                                                            0.5))
  
  plot_grid(plot.attritions_number,
         plot.attrition_percentage,
         align = "h",
         ncol = 2)
  </code></pre>
  
  <p>I get the error:</p>
  
  <pre><code>&gt; plot_grid(plot.attritions_number,
  +           plot.attrition_percentage,
  +           align = "h",
  +           ncol = 2)
  Error in plot_grid(plot.attritions_number, plot.attrition_percentage,  : 
    could not find function "plot_grid"
  </code></pre>
  
  <p>I googled the error but didn't find solution.</p>
  
  <p>what I'm after is that graph:</p>
  
  <p>may any of you help in that?</p>
  
  <p><a href="https://i.stack.imgur.com/yx2TU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/yx2TU.png" alt="enter image description here"></a></p>