Code Reviewer

Thank you for sharing the code and details about your project. Here's a review considering your provided context and guidelines:

PEP 8 Adherence: Your code adheres to the PEP 8 style guide. The naming of your class and methods is consistent with the guide, and your use of spacing and indentation is correct as well.
Docstrings: It is a good practice to include docstrings in your code. Docstrings provide a convenient way of associating documentation with Python modules, functions, classes, and methods. For example, you could add a docstring to your get_details method:
def get_details(self):
    """
    Returns a formatted string containing the employee's name, age, and department.
    """
    return f"Name: {self.name}, Age: {self.age}, Department: {self.department}"

Use of f-strings: You're using f-strings, which is a modern and efficient way of formatting strings in Python. Good job!
Class Design: The class design is straightforward and the method names are self-explanatory, which is good for readability. However, depending on your project, you might want to add more methods for handling employee-specific logic (for example, changing an employee's department, or calculating the years until retirement).
Efficient Searching: Since you've mentioned you're having trouble with efficient searching, remember that classes like these are usually part of larger systems. If you need to manage and search for employees, you would likely have a separate class (such as EmployeeDatabase) responsible for storing Employee objects and performing operations like adding, removing, and finding employees. This would be a good place to implement an efficient searching mechanism.
Error Handling: Right now, there isn't any error checking in your class. For instance, what if someone inputs a non-string for name, or a non-integer for age? Depending on how this class is used, you may want to add checks and raise appropriate exceptions to catch errors early on.
Type Hints: As a suggestion, you could use type hints which are a new feature from Python 3.5. This can make your code more readable and prevent some bugs. Here's how your code could look:
class Employee:
    def __init__(self, name: str, age: int, department: str):
        self.name = name
        self.age = age
        self.department = department<pre><code>def get_details(self) -> str:
    return f"Name: {self.name}, Age: {self.age}, Department: {self.department}"


Remember, the most important aspects of code are that it does what it's supposed to do, and that it's easy for others (and future you) to understand. Your current class does well in these aspects. Good job and keep coding!