code: def elements_and_dtype(elements, dtype, source=None):
      if source is None:
          prefix = ""
      else:
          prefix = f"{source}."
  
      if elements is not None:
          check_strategy(elements, f"{prefix}elements")
      else:
          with check("dtype is not None"):
              if dtype is None:
                  raise InvalidArgument(
                      f"At least one of {prefix}elements or {prefix}dtype must be provided."
                  )
  
      with check("isinstance(dtype, CategoricalDtype)"):
          if pandas.api.types.CategoricalDtype.is_dtype(dtype):
              raise InvalidArgument(
                  f"{prefix}dtype is categorical, which is currently unsupported"
              )
  
      if isinstance(dtype, type) and issubclass(dtype, IntegerDtype):
          raise InvalidArgument(
              f"Passed {dtype=} is a dtype class, please pass in an instance of this class."
              "Otherwise it would be treated as dtype=object"
          )
  
      if (
          isinstance(dtype, type)
          and np.dtype(dtype).kind == "O"
          and dtype is not object
      ):
          err_msg = f"Passed {dtype=} is not a valid Pandas dtype."
          if issubclass(dtype, datetime):
              err_msg += ' To generate valid datetimes, pass `dtype="datetime64[ns]"`'
              raise InvalidArgument(err_msg)
          elif issubclass(dtype, timedelta):
              err_msg += ' To generate valid timedeltas, pass `dtype="timedelta64[ns]"`'
              raise InvalidArgument(err_msg)
          note_deprecation(
              f"{err_msg}  We'll treat it as "
              "dtype=object for now, but this will be an error in a future version.",
              since="2021-12-31",
              has_codemod=False,
              stacklevel=1,
          )
  
      if isinstance(dtype, st.SearchStrategy):
          raise InvalidArgument(
              f"Passed {dtype=} is a strategy, but we require a concrete dtype "
              "here.  See https://stackoverflow.com/q/74355937 for workaround patterns."
          )
  
      _get_subclasses = getattr(IntegerDtype, "__subclasses__", list)
      dtype = {t.name: t() for t in _get_subclasses()}.get(dtype, dtype)
  
      if isinstance(dtype, IntegerDtype):
          is_na_dtype = True
          dtype = np.dtype(dtype.name.lower())
      elif dtype is not None:
          is_na_dtype = False
          dtype = try_convert(np.dtype, dtype, "dtype")
      else:
          is_na_dtype = False
  
      if elements is None:
          elements = npst.from_dtype(dtype)
          if is_na_dtype:
              elements = st.none() | elements
      elif dtype is not None:
  
          def convert_element(value):
              if is_na_dtype and value is None:
                  return None
              name = f"draw({prefix}elements)"
              try:
                  return np.array([value], dtype=dtype)[0]
              except (TypeError, ValueError):
                  raise InvalidArgument(
                      "Cannot convert %s=%r of type %s to dtype %s"
                      % (name, value, type(value).__name__, dtype.str)
                  ) from None
  
          elements = elements.map(convert_element)
      assert elements is not None
  
      return elements, dtype
  
imports: from collections import OrderedDict, abc
  from copy import copy
  from datetime import datetime, timedelta
  from typing import Any, List, Optional, Sequence, Set, Union
  import attr
  import numpy
  import pandas
  from hypothesis import strategies
  from hypothesis._settings import note_deprecation
  from hypothesis.control import reject
  from hypothesis.errors import InvalidArgument
  from hypothesis.extra import numpy
  from hypothesis.internal.conjecture import utils
  from hypothesis.internal.coverage import check, check_function
  from hypothesis.internal.reflection import get_pretty_function_description
  from hypothesis.internal.validation import check_type, check_valid_interval, check_valid_size, try_convert
  from hypothesis.strategies._internal.strategies import Ex, check_strategy
  from hypothesis.strategies._internal.utils import cacheable, defines_strategy
label_desc: Use image node_id 3 for calling a global function with example usage: elements_and_dtype(elements, dtype, source) and returns: elements,  dtype, None, np