diff --git a/.gitignore b/.gitignore
index 68b819a..f2adf56 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
-*.test.py
\ No newline at end of file
+*.test.py
+*.pyc
\ No newline at end of file
diff --git a/u2/list_ops.py b/u2/list_ops.py
new file mode 100644
index 0000000..533adbc
--- /dev/null
+++ b/u2/list_ops.py
@@ -0,0 +1,32 @@
+def append(list1: list, list2: list) -> list:
+    return list1 + list2
+def concat(lists: list[list]) -> list:  
+    fin = []
+    for l in lists:
+        fin += l
+    return fin
+def filter(function, list: list) -> list: 
+    fin = []
+    for x in list:
+        if(function(x)):
+            fin.append(x)
+    return fin
+def length(list: list): 
+    return len(list)
+def map(function, list: list) -> list: 
+    fin = []
+    for x in list:
+        fin.append(function(x))
+    return fin
+def foldl(function, list: list, initial: any) -> any:
+    acc = initial
+    for x in list:
+        acc = function(acc, x)
+    return acc
+def foldr(function, list: list, initial: any) -> any: 
+    acc = initial
+    for x in list[::-1]:
+        acc = function(acc, x)
+    return acc
+def reverse(list: list) -> list: 
+    return list[::-1]
diff --git a/u3/flatten_array.py b/u3/flatten_array.py
new file mode 100644
index 0000000..aca61ff
--- /dev/null
+++ b/u3/flatten_array.py
@@ -0,0 +1,8 @@
+def flatten(l) -> list:
+    acc = []
+    for x in l:
+        if(isinstance(x, list)):
+            acc += flatten(x)
+        elif(x is not None):
+            acc.append(x)
+    return acc
\ No newline at end of file
diff --git a/u4/word_count.py b/u4/word_count.py
index bb887a6..89e8316 100644
--- a/u4/word_count.py
+++ b/u4/word_count.py
@@ -1,30 +1,23 @@
 from collections import defaultdict
 
+def isalnum_without_apostroph(ch: str):
+    return ch.isalnum() and ch != "'"
 def count_words(sentance: str) -> dict:
     sent_list = list(sentance)
     words = defaultdict(int)
 
-    SPECIAL_CHAR = oct(7)
-
-    delims = ":?!\n\t,._&@$^&*()%"
-    del_chars = '"'
-
-    forbidden = list(delims) + list(del_chars) + [" ", "'", ""]
-
     for i, ch in enumerate(sent_list):
-        if(ch in delims):
-            sent_list[i] = " "
-        elif(ch in del_chars):
-            sent_list[i] = ""
         if(ch == "'"):
-            if((sent_list[max(i-1, 0)] not in forbidden) and (sent_list[min(i+1, len(sent_list)-1)] not in forbidden)):
-                sent_list[i] = SPECIAL_CHAR
+            if((isalnum_without_apostroph(sent_list[max(i-1, 0)])) and (isalnum_without_apostroph(sent_list[min(i+1, len(sent_list)-1)]))):
+                pass
             else:
-                sent_list[i] = ""
+                sent_list[i] = " "
+        elif(not ch.isalnum()):
+            sent_list[i] = " "
 
     for w in ''.join(sent_list).lower().split(" "):
-        if w == "":
+        if not len(w):
             continue
-        words[w.replace(SPECIAL_CHAR, "'")] += 1
+        words[w] += 1
 
     return dict(words)