Implemented multi-error handling in MultiError() class (#614)

* Implemented multi-error handling in MultiError() class

* Added newsfragement file and test

* updated doc-string and list-struct

* updating docstring

libp2p/exceptions.py

@@ -1,3 +1,8 @@
+from collections.abc import (
+    Sequence,
+)
+
+
 class BaseLibp2pError(Exception):
     pass
 
@@ -11,6 +16,38 @@ class ParseError(BaseLibp2pError):
 
 
 class MultiError(BaseLibp2pError):
-    """Raised with multiple exceptions."""
+    r"""
+    A combined error that wraps multiple exceptions into a single error object.
+    This error is raised when multiple exceptions need to be reported together,
+    typically in scenarios where parallel operations or multiple validations fail.
 
-    # todo: find some way for this to fancy-print all encapsulated errors
+    Example\:
+    ---------
+        >>> from libp2p.exceptions import MultiError
+        >>> errors = [
+        ...     ValueError("Invalid input"),
+        ...     TypeError("Wrong type"),
+        ...     RuntimeError("Operation failed")
+        ... ]
+        >>> multi_error = MultiError(errors)
+        >>> print(multi_error)
+        Error 1: Invalid input
+        Error 2: Wrong type
+        Error 3: Operation failed
+
+    Note\:
+    ------
+        The string representation of this error will number and list all contained
+        errors sequentially, making it easier to identify individual issues in
+        complex error scenarios.
+
+    """
+
+    def __init__(self, errors: Sequence[Exception]) -> None:
+        super().__init__(errors)
+        self.errors = errors  # Storing list of errors
+
+    def __str__(self) -> str:
+        return "\n".join(
+            f"Error {i + 1}: {error}" for i, error in enumerate(self.errors)
+        )

newsfragments/613.feature.rst

@@ -0,0 +1 @@
+Added support for multiple-error formatting in the `MultiError` class.

tests/exceptions/test_exceptions.py

@@ -0,0 +1,13 @@
+from libp2p.exceptions import (
+    MultiError,
+)
+
+
+def test_multierror_str_and_storage():
+    errors = [ValueError("bad value"), KeyError("missing key"), "custom error"]
+    multi_error = MultiError(errors)
+    # Check for storage
+    assert multi_error.errors == errors
+    # Check for representation
+    expected = "Error 1: bad value\n" "Error 2: 'missing key'\n" "Error 3: custom error"
+    assert str(multi_error) == expected