Fix pylint issues

Author: WardBrian

cmdstanpy/install_cmdstan.py

@@ -523,6 +523,8 @@ def retrieve_version(version: str, progress: bool = True) -> None:
         first = tar.next()
         if first is not None:
             top_dir = first.name
+        else:
+            top_dir = ''
         cmdstan_dir = f'cmdstan-{version}'
         if top_dir != cmdstan_dir:
             raise CmdStanInstallError(

cmdstanpy/install_cxx_toolchain.py

@@ -235,8 +235,10 @@ def get_toolchain_name() -> str:
     return ''
 
 
+# TODO(2.0): drop 3.5 support
 def get_url(version: str) -> str:
     """Return URL for toolchain."""
+    url = ''
     if platform.system() == 'Windows':
         if version == '4.0':
             # pylint: disable=line-too-long
@@ -277,6 +279,8 @@ def run_rtools_install(args: Dict[str, Any]) -> None:
 
     if 'verbose' in args:
         verbose = args['verbose']
+    else:
+        verbose = False
 
     install_dir = args['dir']
     if install_dir is None:

cmdstanpy/utils/stancsv.py

@@ -116,6 +116,7 @@ def scan_optimize_csv(path: str, save_iters: bool = False) -> Dict[str, Any]:
                 all_iters[i, :] = [float(x) for x in xs]
             if i == iters - 1:
                 mle: np.ndarray = np.array(xs, dtype=float)
+    # pylint: disable=possibly-used-before-assignment
     dict['mle'] = mle
     if save_iters:
         dict['all_iters'] = all_iters