Add detailed docstrings for WEATHER_KEYS, POA_KEYS, and TEMPERATURE_KEYS

Author: Chirag3841

pvlib/modelchain.py

@@ -5,27 +5,20 @@
 library. With great power comes great responsibility: users should take
 the time to read the source code for the module.
 """
-
 from functools import partial
 import itertools
 import warnings
 import pandas as pd
 from dataclasses import dataclass, field
 from typing import Union, Tuple, Optional, TypeVar
-
 from pvlib import pvsystem, iam
 import pvlib.irradiance  # avoid name conflict with full import
 from pvlib.pvsystem import _DC_MODEL_PARAMS
 from pvlib.tools import _build_kwargs
-
 from pvlib._deprecation import deprecated
-
-# keys that are used to detect input data and assign data to appropriate
-# ModelChain attribute
-
-# For ModelChain.weather:  
-# Maps weather-related input columns to the weather DataFrame.
-#: list[str]: Required or optional weather input columns.
+# Keys used to detect input data and assign values to the appropriate
+# ModelChain attributes.
+# Weather-related input columns for ModelChain.weather
 WEATHER_KEYS = (
     'ghi',               # Global Horizontal Irradiance (W/m^2)
     'dhi',               # Diffuse Horizontal Irradiance (W/m^2)
@@ -34,30 +27,23 @@
     'temp_air',          # Ambient air temperature (°C)
     'precipitable_water' # Column precipitable water (cm)
 )
-
-# For ModelChain.total_irrad:
-# Plane-of-array irradiance components.
-#: list[str]: Required POA irradiance input columns.
+# Plane-of-array irradiance input columns for ModelChain.total_irrad
 POA_KEYS = (
     'poa_global',   # Total plane-of-array irradiance (W/m^2)
-    'poa_direct',   # Direct normal POA irradiance (W/m^2)
+    'poa_direct',   # Direct POA irradiance (W/m^2)
     'poa_diffuse'   # Diffuse POA irradiance (W/m^2)
 )
-
-# Optional keys for temperature-specific inputs.
-# These override or supplement temperature models.
-#: list[str]: Temperature-related input columns.
+# Temperature-related optional input columns for ModelChain
 TEMPERATURE_KEYS = (
     'module_temperature', # Back-surface module temperature (°C)
     'cell_temperature',   # Direct cell temperature input (°C)
 )
+# All supported input keys combined
 DATA_KEYS = WEATHER_KEYS + POA_KEYS + TEMPERATURE_KEYS
-
 # these dictionaries contain the default configuration for following
 # established modeling sequences. They can be used in combination with
 # ModelChain, particularly they are used by the methods
 # ModelChain.with_pvwatts, ModelChain.with_sapm, etc.
-
 # pvwatts documentation states that it uses the following reference for
 # a temperature model: Fuentes, M. K. (1987). A Simplified Thermal Model
 # for Flat-Plate Photovoltaic Arrays. SAND85-0330. Albuquerque, NM: