Import "matplotlib.pyplot" could not be resolved from source -Python

I got this following error while running python program "Import "matplotlib.pyplot" could not be resolved from source".

PYTHON CODE:

import pandas as pd
import matplotlib.pyplot as plt

df_production =pd.read_csv("monthly-milk-production-pounds.csv")
# df_production.head()
# df_production.tail()

df_production["date"]=pd.to_datetime(df_production['Month'])

df_production.set_index("date",inplace=True)
df_production.index.freq="MS"

df_production["Monthly milk production (pounds per cow)"].plot(figsize=(20,3))
plt.title("Production",size=25)
plt.show()

SOLUTION:

pip install matplotlib

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