input: Write a function to convert a given SQL statement into a Python Pandas DataFrame. The function should accept a SQL query and a database connection as input, execute the query, and return the resulting DataFrame.
  
  def sql_to_dataframe(sql_query, conn):
      import pandas as pd
      return pd.read_sql_query(sql_query, conn)
  
  assert sql_to_dataframe("SELECT * FROM book;", conn).equals(pd.DataFrame({'id': [1, 2], 'title': ['Book A', 'Book B'], 'author': ['Author A', 'Author B']}))
  assert sql_to_dataframe("SELECT title FROM book WHERE id = 1;", conn).equals(pd.DataFrame({'title': ['Book A']}))
  assert sql_to_dataframe("SELECT * FROM book WHERE author = 'Author A';", conn).equals(pd.DataFrame({'id': [1], 'title': ['Book A'], 'author': ['Author A']}))
  assert sql_to_dataframe("SELECT * FROM book WHERE 1 = 0;", conn).empty
  assert sql_to_dataframe("", conn).empty
output: def sql_to_dataframe(sql_query, conn):
      import pandas as pd
      return pd.read_sql_query(sql_query, conn)