title: Folium unable to add multiple points with "same" icon
body: <p>I'm having trouble adding multiple markers with same icon style in folium.</p>
  <p>First I declared icon:</p>
  <pre><code>icon_blue = folium.Icon(color='blue', icon_color='white', icon='info-sign')
  </code></pre>
  <p>Later on I wrote</p>
  <pre><code>folium.Marker(
      location=latlng_start,
      popup=text_start,
      tooltip=text_start,
      name=text_start,
      icon=icon_blue,
  ).add_to(map1)
  
  folium.Marker(
      location=latlng_end,
      popup=text_end,
      tooltip=text_end,
      name=text_end,
      icon=icon_blue,
  ).add_to(map1)
  </code></pre>
  <p>And when I do this, I get output like:</p>
  <p><a href="https://i.stack.imgur.com/vEOMF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/vEOMF.png" alt="enter image description here" /></a></p>
  <p>Basically, a singleton point, with no tooltip or any data attached to it.</p>
  <p>The issue disappears when I delete <code>icon=icon_blue</code> but it also disappears if I make a copy of <code>icon_blue</code>:</p>
  <pre><code>icon_blue_copy = folium.Icon(color='blue', icon_color='white', icon='info-sign')
  </code></pre>
  <p>And then for the second one write:</p>
  <pre><code>folium.Marker(
      location=latlng_end,
      popup=text_end,
      tooltip=text_end,
      name=text_end,
      icon=icon_blue_copy,
  ).add_to(map1)
  </code></pre>
  <p>To get desired output</p>
  <p><a href="https://i.stack.imgur.com/ichHD.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ichHD.png" alt="enter image description here" /></a></p>
  <p>The problem is, why do I need to make these copies? is this some sort of Folium bug, or is this something to do with python?</p>