Solution

app/main.py

@@ -1 +1,77 @@
-# write your code here
+from dataclasses import dataclass, field
+from datetime import datetime
+from typing import List
+import pickle
+
+
+# Data Classes
+
+@dataclass
+class Specialty:
+    name: str
+    number: int
+
+
+@dataclass
+class Student:
+    first_name: str
+    last_name: str
+    birth_date: datetime
+    average_mark: float
+    has_scholarship: bool
+    phone_number: str
+    address: str
+
+
+@dataclass
+class Group:
+    specialty: Specialty
+    course: int
+    students: List[Student] = field(default_factory=list)
+
+
+# Pickle Functions
+def write_groups_information(groups: List[Group]) -> int:
+    """
+    Writes all inputted groups to 'groups.pickle' using pickle.
+    Returns the maximum number of students in any group.
+    """
+    with open("groups.pickle", "wb") as f:
+        pickle.dump(groups, f)
+
+    max_students = max((len(group.students) for group in groups), default=0)
+    return max_students
+
+
+def write_students_information(students: List[Student]) -> int:
+    """
+    Writes all students to 'students.pickle' using pickle.
+    Returns the total number of students.
+    """
+    with open("students.pickle", "wb") as f:
+        pickle.dump(students, f)
+
+    return len(students)
+
+
+def read_groups_information() -> List[str]:
+    """
+    Reads groups from 'groups.pickle' and returns a list of
+    specialties' names without repetition.
+    """
+    with open("groups.pickle", "rb") as f:
+        groups: List[Group] = pickle.load(f)
+
+    specialties = {group.specialty.name for group in groups}
+    return list(specialties)
+
+
+def read_students_information() -> List[Student]:
+    """
+    Reads all students from 'students.pickle' and returns
+    them as a list of Student instances.
+    """
+    with open("students.pickle", "rb") as f:
+        students: List[Student] = pickle.load(f)
+
+    return students