input: Write a function to read a CSV file into a pandas DataFrame.
  assert read_csv_to_df("data.csv").equals(pd.DataFrame(pd.read_csv("data.csv")))
  assert isinstance(read_csv_to_df("data.csv"), pd.DataFrame)
  assert not read_csv_to_df("data.csv").empty
output: import pandas as pd
  
  def read_csv_to_df(file_path):
      return pd.read_csv(file_path)