input: Write a function to convert a given SQL statement into a Python Pandas DataFrame. The function should take a SQL query as an input string and a database connection object, and return a Pandas DataFrame containing the results of the query.
  
  def sql_to_pandas(sql_query, conn):
      import pandas as pd
      return pd.read_sql_query(sql_query, conn)
  
  assert isinstance(sql_to_pandas("SELECT * FROM book;", conn), pd.DataFrame) == True
  assert isinstance(sql_to_pandas("SELECT title, author FROM book WHERE year > 2000;", conn), pd.DataFrame) == True
  assert isinstance(sql_to_pandas("SELECT * FROM author;", conn), pd.DataFrame) == True
  assert isinstance(sql_to_pandas("SELECT * FROM publisher LIMIT 5;", conn), pd.DataFrame) == True
  assert isinstance(sql_to_pandas("", conn), pd.DataFrame) == True
output: def sql_to_pandas(sql_query, conn):
      import pandas as pd
      return pd.read_sql_query(sql_query, conn)