docs: def numpy_to_weld_type(np_dtype):
      """Convert from NumPy dtype to Weld type.
  
      Note that support for strings is intended to be only for
      Python 2 str and Python 3 bytes. No unicode.
  
      Parameters
      ----------
      np_dtype : numpy.dtype or str
          NumPy dtype.
  
      Returns
      -------
      WeldType
          Corresponding WeldType.
  
      Examples
      --------
      >>> import numpy as np
      >>> from baloo.weld import numpy_to_weld_type
      >>> str(numpy_to_weld_type(np.dtype(np.int64)))
      'i64'
      >>> str(numpy_to_weld_type('?'))
      'bool'
  
      """
      if not isinstance(np_dtype, (str, bytes, np.dtype, type)):
          raise TypeError('Can only convert np.dtype or str')
  
      if isinstance(np_dtype, (str, bytes, type)):
          np_dtype = np.dtype(np_dtype)
  
      return _numpy_to_weld_type_mapping[np_dtype.char]