remove IPython from requirements

Author: toumix

discopy/drawing.py

@@ -8,7 +8,6 @@
 
 import networkx as nx
 from PIL import Image
-from IPython.display import HTML
 import matplotlib.pyplot as plt
 from matplotlib.path import Path
 from matplotlib.patches import PathPatch
@@ -327,7 +326,11 @@ def to_gif(diagram, *diagrams, path=None,
         frames[0].save(path, format='GIF', append_images=frames[1:],
                        save_all=True, duration=timestep,
                        **{'loop': 0} if loop else {})
-        return HTML('<img src="{}">'.format(path))
+        try:
+            from IPython.display import HTML
+            return HTML('<img src="{}">'.format(path))
+        except ImportError:
+            return '<img src="{}">'.format(path)
 
 
 def pregroup_draw(words, cups, **params):

requirements.txt

@@ -1,4 +1,3 @@
-ipython>=7.10.1
 numpy>=1.18.1
 networkx>=2.4
 matplotlib>=3.1.2