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Given the following text problem statement, write Python code to implement the functionality described below in problem statement
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Problem:
I have this Pandas dataframe (df):
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Python Code:
import pandas as pd
df = pd.DataFrame({'A': [1, 2, 's', 3, 'b'],
                   'B': ['green', 'red', 'blue', 'yellow', 'black']})
def g(df):
    return df[pd.to_numeric(df.A, errors='coerce').notnull()]
result = g(df.copy())
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