I need to calculate the shape area (and possible the perimiter) of polygons for over 300 files. I tried to use a Python code but I am not very familiar with Python so when it returns an error I do not know where the problem is. My Python code looks like this:

```
import arcpy
from arcpy import env
import os
import csv

outputFilePath = 'outputPath'
sourceFolderPath = 'inputPath'

for root, dirs, files in arcpy.da.Walk(sourceFolderPath):
    for name in files:
        if name[-4:] == '.shp':
            arcpy.env.workspace = os.path.join(root, name)
            arcpy.AddField_management(name[:-4], "Shape_area", "DOUBLE")
            arcpy.CalculateField_management(name[:-4], outputFilePath + '/' + name[:-4], "Shape_area", "PYTHON_9.3")

```

I received this error message:

```
Traceback (most recent call last):
  File "<string>", line 15, in <module>
  File "c:\program files\arcgis\pro\Resources\arcpy\arcpy\management.py", line 3290, in CalculateField
    raise e
  File "c:\program files\arcgis\pro\Resources\arcpy\arcpy\management.py", line 3287, in CalculateField
    retval = convertArcObjectToPythonObject(gp.CalculateField_management(*gp_fixargs((in_table, field, expression, expression_type, code_block), True)))
  File "c:\program files\arcgis\pro\Resources\arcpy\arcpy\geoprocessing\_base.py", line 506, in <lambda>
    return lambda *args: val(*gp_fixargs(args, True))
arcgisscripting.ExecuteError: Failed to execute. Parameters are not valid.

```

Any suggestions?