From ac6442a190922d0bbd8f7b19b85bd398a043ce8c Mon Sep 17 00:00:00 2001
From: Radoslav Pitonak <rado.pitonak@gmail.com>
Date: Thu, 15 Mar 2018 23:20:59 +0000
Subject: [PATCH 1/2] TryteString.random() use cls.LEN as its default length,
 when available

---
 iota/types.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/iota/types.py b/iota/types.py
index 70372f9..d19f1cc 100644
--- a/iota/types.py
+++ b/iota/types.py
@@ -49,7 +49,7 @@ class TryteString(JsonSerializable):
   IMPORTANT: A TryteString does not represent a numeric value!
   """
   @classmethod
-  def random(cls, length):
+  def random(cls, length=None):
     # type: (int) -> TryteString
     """
     Generates a random sequence of trytes.
@@ -60,6 +60,12 @@ def random(cls, length):
     alphabet  = list(itervalues(AsciiTrytesCodec.alphabet))
     generator = SystemRandom()
 
+    try:
+      length = length or cls.LEN
+    except AttributeError:  # class has no LEN attribute
+      if length is None:
+        raise TypeError("random() missing 1 required positional argument: 'length'")
+
     # :py:meth:`SystemRandom.choices` wasn't added until Python 3.6;
     # for compatibility, we will continue to use ``choice`` in a loop.
     # https://docs.python.org/3/library/random.html#random.choices

From aae0cf0042bd84799de40c16eac07c29d582132f Mon Sep 17 00:00:00 2001
From: Radoslav Pitonak <rado.pitonak@gmail.com>
Date: Mon, 2 Jul 2018 13:54:24 +0100
Subject: [PATCH 2/2] explicit is None check, better error message

---
 iota/types.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/iota/types.py b/iota/types.py
index d19f1cc..26b25ed 100644
--- a/iota/types.py
+++ b/iota/types.py
@@ -61,10 +61,14 @@ def random(cls, length=None):
     generator = SystemRandom()
 
     try:
-      length = length or cls.LEN
+      if length is None:
+        length = cls.LEN
+
+      if length <= 0:
+        raise TypeError("length parameter needs to be greater than zero")
     except AttributeError:  # class has no LEN attribute
       if length is None:
-        raise TypeError("random() missing 1 required positional argument: 'length'")
+        raise TypeError("{class_name} does not define a length property".format(class_name=cls.__name__))
 
     # :py:meth:`SystemRandom.choices` wasn't added until Python 3.6;
     # for compatibility, we will continue to use ``choice`` in a loop.