Proper way to indicate ColorDistance needs numpy

mathics/builtin/compilation.py

@@ -170,9 +170,6 @@ def __str__(self):
         return "-CompiledCode-"
 
     def boxes_to_text(self, leaves=None, **options):
-        from trepan.api import debug
-
-        debug()
         if not leaves:
             leaves = self._leaves
         return "-CompiledCode-"

mathics/builtin/graphics.py

@@ -851,6 +851,10 @@ class ColorDistance(Builtin):
         + "two lists of colors of the same length.",
     }
 
+    # If numpy is not installed, 100 * c1.to_color_space returns
+    # a list of 100 x 3 elements, instead of doing elementwise multiplication
+    requires = ("numpy",)
+
     # the docs say LABColor's colorspace corresponds to the CIE 1976 L^* a^* b^* color space
     # with {l,a,b}={L^*,a^*,b^*}/100. Corrections factors are put accordingly.
 
@@ -887,13 +891,6 @@ class ColorDistance(Builtin):
     def apply(self, c1, c2, evaluation, options):
         "ColorDistance[c1_, c2_, OptionsPattern[ColorDistance]]"
 
-        # If numpy is not installed, 100 * c1.to_color_space returns
-        # a list of 100 x 3 elements, instead of doing elementwise multiplication
-        try:
-            import numpy as np
-        except:
-            raise RuntimeError("NumPy needs to be installed for ColorDistance")
-
         distance_function = options.get("System`DistanceFunction")
         compute = None
         if isinstance(distance_function, String):

mathics/formatter/svg.py

@@ -27,7 +27,6 @@
 
 class _SVGTransform:
     def __init__(self):
-        from trepan.api import debug; debug()
         self.transforms = []
 
     def matrix(self, a, b, c, d, e, f):