code: def check_table(table):
      
      if not type(table) is list:
          return "Table must be a list of lists"
  
      if len(table) == 0:
          return "Table must contain at least one row and one column"
  
      for i in range(len(table)):
          if not type(table[i]) is list:
              return "Table must be a list of lists"
          if not len(table[i]) == len(table[0]):
              "Each row must have the same number of columns"
  
      return ""
docs: Ensure the table is valid for converting to grid table.
  
      * The table must a list of lists
      * Each row must contain the same number of columns
      * The table must not be empty
  
      Parameters
      ----------
      table : list of lists of str
          The list of rows of strings to convert to a grid table
  
      Returns
      -------
      message : str
          If no problems are found, this message is empty, otherwise it
          tries to describe the problem that was found.