Extract common `is_list_or_tuple' function

Issue:
https://github.com/genenetwork/gn-gemtext-threads/blob/main/topics/gn1-migration-to-gn2/clustering.gmi

* Extract the common function `is_list_or_tuple' making it accessible to later
  parts of the code.

1 files changed, 5 insertions, 4 deletions

diff --git a/gn3/computations/slink.py b/gn3/computations/slink.py
index 3156b31..b15c058 100644
--- a/gn3/computations/slink.py
+++ b/gn3/computations/slink.py
@@ -4,10 +4,11 @@ class LengthError(BaseException):
 class MirrorError(BaseException):
     pass
 
+def is_list_or_tuple(item):
+    return type(item) in [list, tuple]
+
 def raise_valueerror_if_data_is_not_lists_or_tuples(lists):
     """Check that `lists` is a list of lists: If not, raise an exception."""
-    def is_list_or_tuple(item):
-        return type(item) == type([]) or type(item) == type(tuple)
 
     if (not is_list_or_tuple(lists)) or (not all(map(is_list_or_tuple, lists))):
         raise ValueError("Expected list or tuple")
@@ -72,7 +73,7 @@ This description should be updated once the form/type of 'distance' identified."
     #### END: Guard Functions ####
     if type(i) == int and type(j) == int: # From member i to member j
         return lists[i][j]
-    elif type(i) == int and (type(j) in [list, tuple]):
+    elif type(i) == int and is_list_or_tuple(j):
         return min(map(lambda j_new: nearest(lists, i, j_new), j))
-    elif type(j) == int and (type(i) in [list, tuple]):
+    elif type(j) == int and is_list_or_tuple(i):
         return min(map(lambda i_new: nearest(lists, i_new, j), i))