diff --git a/solc_select/constants.py b/solc_select/constants.py
index 4d696ae..7ba4041 100644
--- a/solc_select/constants.py
+++ b/solc_select/constants.py
@@ -1,15 +1,12 @@
 import os
 from pathlib import Path
 
-# DIRs path
-if "VIRTUAL_ENV" in os.environ:
-    HOME_DIR = Path(os.environ["VIRTUAL_ENV"])
-else:
-    HOME_DIR = Path.home()
-SOLC_SELECT_DIR = HOME_DIR.joinpath(".solc-select")
-ARTIFACTS_DIR = SOLC_SELECT_DIR.joinpath("artifacts")
+# Directory paths
+HOME_DIR = Path(os.environ.get("VIRTUAL_ENV", Path.home()))
+SOLC_SELECT_DIR = HOME_DIR / ".solc-select"
+ARTIFACTS_DIR = SOLC_SELECT_DIR / "artifacts"
 
-# CLI Commands
+# CLI commands
 INSTALL_COMMAND = "install"
 USE_COMMAND = "use"
 VERSIONS_COMMAND = "versions"
diff --git a/solc_select/infrastructure/filesystem.py b/solc_select/infrastructure/filesystem.py
index 5508d8a..46fbbed 100644
--- a/solc_select/infrastructure/filesystem.py
+++ b/solc_select/infrastructure/filesystem.py
@@ -30,20 +30,19 @@ def get_current_version(self) -> SolcVersion | None:
                 return None
 
         global_version_file = self.config_dir / "global-version"
-        if global_version_file.exists():
-            try:
-                with open(global_version_file, encoding="utf-8") as f:
-                    return SolcVersion.parse(f.read().strip())
-            except (OSError, ValueError):
-                return None
+        if not global_version_file.exists():
+            return None
 
-        return None
+        try:
+            version_text = global_version_file.read_text(encoding="utf-8").strip()
+            return SolcVersion.parse(version_text)
+        except (OSError, ValueError):
+            return None
 
     def set_global_version(self, version: SolcVersion) -> None:
         """Set the global version."""
         global_version_file = self.config_dir / "global-version"
-        with open(global_version_file, "w", encoding="utf-8") as f:
-            f.write(str(version))
+        global_version_file.write_text(str(version), encoding="utf-8")
 
     def get_version_source(self) -> str:
         """Get the source of the current version setting."""
@@ -77,17 +76,17 @@ def get_installed_versions(self) -> list[SolcVersion]:
 
         installed = []
         for item in self.artifacts_dir.iterdir():
-            if item.is_dir() and item.name.startswith("solc-"):
-                version_str = item.name.replace("solc-", "")
-                try:
-                    version = SolcVersion.parse(version_str)
-                    if self.is_installed(version):
-                        installed.append(version)
-                except ValueError:
-                    continue
-
-        installed.sort()
-        return installed
+            if not (item.is_dir() and item.name.startswith("solc-")):
+                continue
+            version_str = item.name.removeprefix("solc-")
+            try:
+                version = SolcVersion.parse(version_str)
+                if self.is_installed(version):
+                    installed.append(version)
+            except ValueError:
+                pass
+
+        return sorted(installed)
 
     def is_installed(self, version: SolcVersion) -> bool:
         """Check if a version is installed."""
diff --git a/solc_select/models/artifacts.py b/solc_select/models/artifacts.py
index ecbfdd7..c51b48b 100644
--- a/solc_select/models/artifacts.py
+++ b/solc_select/models/artifacts.py
@@ -33,11 +33,9 @@ def __post_init__(self) -> None:
             raise ValueError("Download URL cannot be empty")
         if not self.checksum_sha256:
             raise ValueError("SHA256 checksum cannot be empty")
-        # Normalize by removing 0x prefix
-        if self.checksum_sha256.startswith("0x"):
-            object.__setattr__(self, "checksum_sha256", self.checksum_sha256[2:])
-        if self.checksum_keccak256 and self.checksum_keccak256.startswith("0x"):
-            object.__setattr__(self, "checksum_keccak256", self.checksum_keccak256[2:])
+        self.checksum_sha256 = self.checksum_sha256.removeprefix("0x")
+        if self.checksum_keccak256:
+            self.checksum_keccak256 = self.checksum_keccak256.removeprefix("0x")
 
     @property
     def is_zip_archive(self) -> bool:
diff --git a/solc_select/models/platforms.py b/solc_select/models/platforms.py
index 4d4bac1..631c23e 100644
--- a/solc_select/models/platforms.py
+++ b/solc_select/models/platforms.py
@@ -25,18 +25,22 @@ def __post_init__(self) -> None:
 
     def get_capability(self) -> PlatformCapability:
         """Get the capability declaration for this platform."""
-        key = f"{self.os_type}-{self.architecture}"
-        return CAPABILITY_REGISTRY.get(key, self._create_default_capability())
+        identifier = self.to_identifier()
+        return CAPABILITY_REGISTRY.get(str(identifier), self._create_default_capability())
 
     def _create_default_capability(self) -> PlatformCapability:
         """Create default capability (native-only, no emulation)."""
-        platform_id = PlatformIdentifier(self.os_type, self.architecture)
+        platform_id = self.to_identifier()
         return PlatformCapability(
             host_platform=platform_id,
             native_support=platform_id,
             emulation_capabilities=[],
         )
 
+    def to_identifier(self) -> PlatformIdentifier:
+        """Convert to a PlatformIdentifier."""
+        return PlatformIdentifier(self.os_type, self.architecture)
+
     @classmethod
     def current(cls) -> "Platform":
         """Get the current system platform."""
diff --git a/solc_select/platform_capabilities.py b/solc_select/platform_capabilities.py
index e01c5cd..3dedb03 100644
--- a/solc_select/platform_capabilities.py
+++ b/solc_select/platform_capabilities.py
@@ -12,6 +12,9 @@ class PlatformIdentifier:
     os_type: str  # 'linux', 'darwin', 'windows'
     architecture: str  # 'amd64', 'arm64'
 
+    def __str__(self) -> str:
+        return f"{self.os_type}-{self.architecture}"
+
 
 @dataclass(frozen=True)
 class EmulationCapability:
diff --git a/solc_select/repositories.py b/solc_select/repositories.py
index 99577b0..430095a 100644
--- a/solc_select/repositories.py
+++ b/solc_select/repositories.py
@@ -26,18 +26,10 @@ def __init__(
         has_latest_release: bool = False,
     ):
         self.session = session
-        self._base_url = base_url
-        self._list_url = list_url
+        self.base_url = base_url
+        self.list_url = list_url
         self._has_latest_release = has_latest_release
 
-    @property
-    def base_url(self) -> str:
-        return self._base_url
-
-    @property
-    def list_url(self) -> str:
-        return self._list_url
-
     @lru_cache(maxsize=5)  # noqa: B019
     def _fetch_list_json(self) -> dict[str, Any]:
         response = self.session.get(self.list_url)
@@ -77,14 +69,10 @@ def get_checksums(self, version: SolcVersion) -> tuple[str, str | None]:
         if not matches or not matches[0]["sha256"]:
             raise ValueError(f"Unable to retrieve checksum for {version}")
 
-        sha256_hash = matches[0]["sha256"]
+        sha256_hash = matches[0]["sha256"].removeprefix("0x")
         keccak256_hash = matches[0].get("keccak256")
-
-        # Normalize checksums by removing 0x prefix if present
-        if sha256_hash and sha256_hash.startswith("0x"):
-            sha256_hash = sha256_hash[2:]
-        if keccak256_hash and keccak256_hash.startswith("0x"):
-            keccak256_hash = keccak256_hash[2:]
+        if keccak256_hash:
+            keccak256_hash = keccak256_hash.removeprefix("0x")
 
         return sha256_hash, keccak256_hash
 
diff --git a/solc_select/services/artifact_manager.py b/solc_select/services/artifact_manager.py
index fa59086..8e06ad2 100644
--- a/solc_select/services/artifact_manager.py
+++ b/solc_select/services/artifact_manager.py
@@ -95,6 +95,23 @@ def verify_checksum(self, artifact: SolcArtifact, file_handle: BufferedRandom) -
         if artifact.checksum_keccak256 and artifact.checksum_keccak256 != local_keccak256:
             raise ChecksumMismatchError(artifact.checksum_keccak256, local_keccak256, "Keccak256")
 
+    def _download_artifact(self, artifact: SolcArtifact) -> None:
+        """Download artifact and verify checksums."""
+        response = self.session.get(artifact.download_url, stream=True)
+        response.raise_for_status()
+
+        with open(artifact.file_path, "w+b", opener=partial(os.open, mode=0o664)) as f:
+            try:
+                for chunk in response.iter_content(chunk_size=8192):
+                    if chunk:
+                        f.write(chunk)
+            except KeyboardInterrupt:
+                if artifact.file_path.exists():
+                    artifact.file_path.unlink(missing_ok=True)
+                raise
+
+            self.verify_checksum(artifact, f)
+
     def download_and_install(self, version: SolcVersion, silent: bool = False) -> bool:
         """Download and install a Solidity compiler version."""
         if self.filesystem.is_installed(version):
@@ -115,21 +132,7 @@ def download_and_install(self, version: SolcVersion, silent: bool = False) -> bo
         self.filesystem.ensure_artifact_directory(version)
 
         try:
-            response = self.session.get(artifact.download_url, stream=True)
-            response.raise_for_status()
-
-            with open(artifact.file_path, "w+b", opener=partial(os.open, mode=0o664)) as f:
-                try:
-                    for chunk in response.iter_content(chunk_size=8192):
-                        if chunk:
-                            f.write(chunk)
-                except KeyboardInterrupt:
-                    # Clean up partially downloaded file on interrupt
-                    if artifact.file_path.exists():
-                        artifact.file_path.unlink(missing_ok=True)
-                    raise
-
-                self.verify_checksum(artifact, f)
+            self._download_artifact(artifact)
 
             if artifact.is_zip_archive:
                 self._extract_zip_archive(artifact)
diff --git a/solc_select/services/platform_service.py b/solc_select/services/platform_service.py
index 83e4580..eeaacc8 100644
--- a/solc_select/services/platform_service.py
+++ b/solc_select/services/platform_service.py
@@ -34,7 +34,7 @@ def warn_about_arm64_compatibility(self, force: bool = False) -> None:
         if self.platform.architecture != "arm64":
             return
 
-        warning_file = SOLC_SELECT_DIR.joinpath(".arm64_warning_shown")
+        warning_file = SOLC_SELECT_DIR / ".arm64_warning_shown"
         if not force and warning_file.exists():
             return
 
diff --git a/solc_select/services/repository_matcher.py b/solc_select/services/repository_matcher.py
index 06e9665..44fcfd9 100644
--- a/solc_select/services/repository_matcher.py
+++ b/solc_select/services/repository_matcher.py
@@ -77,7 +77,7 @@ def find_repository_for_version(
                     if not exact or str(version) in repo.available_versions:
                         return repo, target_platform
 
-        platform_list = ", ".join(str(p) for p in runnable_platforms)
+        platform_list = ", ".join(map(str, runnable_platforms))
         raise VersionNotFoundError(
             str(version),
             available_versions=[],
@@ -124,15 +124,13 @@ def _create_repository(
         repository_id = manifest.repository_id
 
         if repository_id == "soliditylang":
-            platform_obj = Platform(os_type=platform.os_type, architecture=platform.architecture)
+            platform_obj = Platform(platform.os_type, platform.architecture)
             return SoliditylangRepository(platform_obj, self.session)
 
-        factories = {
-            "crytic": CryticRepository,
-            "alloy": AlloyRepository,
-        }
-        factory = factories.get(repository_id)
-        if factory is not None:
-            return factory(self.session)
+        if repository_id == "crytic":
+            return CryticRepository(self.session)
+
+        if repository_id == "alloy":
+            return AlloyRepository(self.session)
 
         raise ValueError(f"Unknown repository: {repository_id}")
diff --git a/solc_select/services/solc_service.py b/solc_select/services/solc_service.py
index 69e0152..16a9fb5 100644
--- a/solc_select/services/solc_service.py
+++ b/solc_select/services/solc_service.py
@@ -48,7 +48,7 @@ def __init__(self, platform: Platform | None = None):
         )
         self.platform_service = PlatformService(platform)
 
-    def get_current_version(self) -> tuple[SolcVersion | None, str]:
+    def get_current_version(self) -> tuple[SolcVersion, str]:
         """Get the current version and its source."""
         version = self.filesystem.get_current_version()
         source = self.filesystem.get_version_source()
@@ -57,8 +57,7 @@ def get_current_version(self) -> tuple[SolcVersion | None, str]:
             raise NoVersionSetError()
 
         if not self.filesystem.is_installed(version):
-            installed_versions = self.filesystem.get_installed_versions()
-            installed_strs = [str(v) for v in installed_versions]
+            installed_strs = [str(v) for v in self.filesystem.get_installed_versions()]
             raise VersionNotInstalledError(str(version), installed_strs, source)
 
         return version, source
@@ -153,9 +152,6 @@ def execute_solc(self, args: list[str]) -> None:
             print(f"Error: {e}", file=sys.stderr)
             sys.exit(1)
 
-        if version is None:
-            sys.exit(1)
-
         binary_path = self.filesystem.get_binary_path(version)
         artifact = self.artifact_manager.create_local_artifact_metadata(version)
 
diff --git a/solc_select/services/version_manager.py b/solc_select/services/version_manager.py
index 3cb3072..2267306 100644
--- a/solc_select/services/version_manager.py
+++ b/solc_select/services/version_manager.py
@@ -76,14 +76,10 @@ def resolve_version_strings(self, version_strings: list[str]) -> list[SolcVersio
         if "all" in version_strings:
             return self.get_available_versions()
 
-        versions = []
-        for version_str in version_strings:
-            if version_str == "latest":
-                versions.append(self.get_latest_version())
-            else:
-                versions.append(self.validate_version(version_str))
-
-        return versions
+        return [
+            self.get_latest_version() if v == "latest" else self.validate_version(v)
+            for v in version_strings
+        ]
 
     def get_installable_versions(self, installed_versions: list[SolcVersion]) -> list[SolcVersion]:
         """Get versions that can be installed (not already installed)."""