code: def schema_from_table(table, schema=None):
      
      schema = schema if schema is not None else {}
      pairs = []
      for name, column in table.columns.items():
          if name in schema:
              dtype = dt.dtype(schema[name])
          else:
              dtype = dt.dtype(
                  getattr(table.bind, 'dialect', SQLAlchemyDialect()),
                  column.type,
                  nullable=column.nullable,
              )
          pairs.append((name, dtype))
      return sch.schema(pairs)
docs: Retrieve an ibis schema from a SQLAlchemy ``Table``.
  
      Parameters
      ----------
      table : sa.Table
  
      Returns
      -------
      schema : ibis.expr.datatypes.Schema
          An ibis schema corresponding to the types of the columns in `table`.