Implemented the transform functions.

It went well. At first it wasn't clear what the scale function was
supposed to do because it also translates the data so it's really more
of a change of coordinates.

transform.py

@@ -6,38 +6,51 @@
 
 def maximum(data):
     "Returns the largest number in data"
-    raise NotImplementedError
+    ans = None
+    for datum in data:
+        if ans is None or datum > ans:
+            ans = datum 
+    return ans
 
 def minimum(data):
     "Returns the smallest number in data"
-    raise NotImplementedError
+    ans = None
+    for datum in data:
+        if ans is None or datum < ans:
+            ans = datum 
+    return ans
 
 def bounds(data):
     "Returns a list of the smallest and largest numbers in data"
-    raise NotImplementedError
+    return [minimum(data), maximum(data)]
 
 def clamp(value, low, high):
     """Clamps a value to a range from low to high. 
     Returns value if it is between low and high.
     If value is lower than low, returns low. If value is higher than high, returns high.
     """
-    raise NotImplementedError
+    if value < low:
+        return low
+    if value > high:
+        return high
+    return value
 
 def ratio(value, start, end):
     """Returns a number from 0.0 to 1.0, representing how far along value is from start to end.
     The return value is clamped to [0, 1], so even if value is lower than start, the return 
     value will not be lower than 0.0.
     """
-    raise NotImplementedError
+    progress = (value - start) / (end - start)
+    return clamp(progress, 0.0, 1.0)
 
 def scale(value, domain_min, domain_max, range_min, range_max):
     "Given a value within a domain, returns the scaled equivalent within range."
-    raise NotImplementedError
+    return range_min + ratio(value, domain_min, domain_max) * (range_max - range_min)
 
 def get_x_values(points):
     "Returns the first value for each point in points."
-    raise NotImplementedError
+    return [x for x, y in points]
 
 def get_y_values(points):
     "Returns the second value for each point in points."
-    raise NotImplementedError
+    return [y for x, y in points]