Move argument parsing to main part of the script

Inst_eddies/Analysis/plot_velocity.py

@@ -6,7 +6,6 @@ that is special to surface ocean current coming from AVISO ADT files.
 """
 
 import sys
-import argparse
 
 import numpy as np
 import cartopy.crs as ccrs
@@ -15,37 +14,8 @@ import netCDF4
 
 import wind_cartopy
 
-def plot_velocity():
-    parser = argparse.ArgumentParser(
-        formatter_class=argparse.ArgumentDefaultsHelpFormatter
-    )
-    parser.add_argument(
-        "-s",
-        "--scale",
-        default=20,
-        type=float,
-        help="scale of arrows for the velocity field",
-    )
-    parser.add_argument(
-        "-w",
-        "--window",
-        help="choose a limited plot window",
-        type=float,
-        nargs=4,
-        metavar=("llcrnrlon", "llcrnrlat", "urcrnrlon", "urcrnrlat"),
-    )
-    parser.add_argument(
-        "--save", metavar="format", help="Save file to specified format"
-    )
-    parser.add_argument(
-        "-u",
-        "--undefined",
-        action="store_true",
-        help="plot points where velocity is not defined",
-    )
-    parser.add_argument("input_file", help="NetCDF file containing velocity")
-    args = parser.parse_args()
 
+def plot_velocity(args):
     with netCDF4.Dataset(args.input_file) as f:
         if "lon" in f.variables:
             lon = "lon"
@@ -126,5 +96,37 @@ def plot_velocity():
     else:
         plt.show()
 
+
 if __name__ == "__main__":
-    plot_velocity()
+    import argparse
+
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter
+    )
+    parser.add_argument(
+        "-s",
+        "--scale",
+        default=20,
+        type=float,
+        help="scale of arrows for the velocity field",
+    )
+    parser.add_argument(
+        "-w",
+        "--window",
+        help="choose a limited plot window",
+        type=float,
+        nargs=4,
+        metavar=("llcrnrlon", "llcrnrlat", "urcrnrlon", "urcrnrlat"),
+    )
+    parser.add_argument(
+        "--save", metavar="format", help="Save file to specified format"
+    )
+    parser.add_argument(
+        "-u",
+        "--undefined",
+        action="store_true",
+        help="plot points where velocity is not defined",
+    )
+    parser.add_argument("input_file", help="NetCDF file containing velocity")
+    args = parser.parse_args()
+    plot_velocity(args)