input: Write a function to generate an HTML page containing a table with the given employee data. The function should take a list of dictionaries where each dictionary represents an employee with keys 'Name', 'Job Title', 'Department', and 'Salary'. The function should return the complete HTML string representing the table. If the input list is empty, the function should return an empty string.
  assert generate_employee_table([
      {'Name': 'John Doe', 'Job Title': 'Senior Developer', 'Department': 'IT', 'Salary': '$120,000'},
      {'Name': 'Jane Doe', 'Job Title': 'Manager', 'Department': 'Finance', 'Salary': '$95,000'},
      {'Name': 'Tim Smith', 'Job Title': 'Junior Developer', 'Department': 'IT', 'Salary': '$55,000'}
  ]) == '<html>\n  <head>\n    <title>Employee Data</title>\n  </head>\n  <body>\n    <table>\n      <thead>\n        <tr>\n          <th>Name</th>\n          <th>Job Title</th>\n          <th>Department</th>\n          <th>Salary</th>\n        </tr>\n      </thead>\n      <tbody>\n        <tr>\n          <td>John Doe</td>\n          <td>Senior Developer</td>\n          <td>IT</td>\n          <td>$120,000</td>\n        </tr>\n        <tr>\n          <td>Jane Doe</td>\n          <td>Manager</td>\n          <td>Finance</td>\n          <td>$95,000</td>\n        </tr>\n        <tr>\n          <td>Tim Smith</td>\n          <td>Junior Developer</td>\n          <td>IT</td>\n          <td>$55,000</td>\n        </tr>\n      </tbody>\n    </table>\n  </body>\n</html>'
  assert generate_employee_table([]) == ''
output: def generate_employee_table(employees):
      if not employees:
          return ''
      html = '<html>\n  <head>\n    <title>Employee Data</title>\n  </head>\n  <body>\n    <table>\n      <thead>\n        <tr>\n          <th>Name</th>\n          <th>Job Title</th>\n          <th>Department</th>\n          <th>Salary</th>\n        </tr>\n      </thead>\n      <tbody>'
      for employee in employees:
          html += f'\n        <tr>\n          <td>{employee["Name"]}</td>\n          <td>{employee["Job Title"]}</td>\n          <td>{employee["Department"]}</td>\n          <td>{employee["Salary"]}</td>\n        </tr>'
      html += '\n      </tbody>\n    </table>\n  </body>\n</html>'
      return html