python 3.8 fixes

pyzx/graph/base.py

@@ -480,7 +480,7 @@ def to_matrix(self,preserve_scalar:bool=True) -> np.ndarray:
         """Returns a representation of the graph as a matrix using :func:`~pyzx.tensor.tensorfy`"""
         return tensor_to_matrix(tensorfy(self, preserve_scalar), self.num_inputs(), self.num_outputs())
 
-    def to_dict(self, include_scalar:bool=True) -> dict[str, Any]:
+    def to_dict(self, include_scalar:bool=True) -> Dict[str, Any]:
         """Returns a json representation of the graph that follows the Quantomatic .qgraph format.
         Convert back into a graph using :meth:`from_json`."""
         from .jsonparser import graph_to_dict

pyzx/graph/jsonparser.py

@@ -71,7 +71,7 @@ def _new_var(name: str) -> Poly:
         except Exception as e:
             raise ValueError(e)
 
-def json_to_graph(js: str|dict[str,Any], backend:Optional[str]=None) -> BaseGraph:
+def json_to_graph(js: Union[str,dict[str,Any]], backend:Optional[str]=None) -> BaseGraph:
     """Converts the json representation of a .qgraph Quantomatic graph into
     a pyzx graph. If JSON is given as a string, parse it first."""
     if isinstance(js, str):
@@ -181,7 +181,7 @@ def json_to_graph(js: str|dict[str,Any], backend:Optional[str]=None) -> BaseGrap
 
     return g
 
-def graph_to_dict(g: BaseGraph[VT,ET], include_scalar: bool=True) -> dict[str, Any]:
+def graph_to_dict(g: BaseGraph[VT,ET], include_scalar: bool=True) -> Dict[str, Any]:
     """Converts a PyZX graph into Python dict for JSON output.
     If include_scalar is set to True (the default), then this includes the value
     of g.scalar with the json, which will also be loaded by the ``from_json`` method."""

pyzx/graph/scalar.py

@@ -20,7 +20,7 @@
 import cmath
 import copy
 from fractions import Fraction
-from typing import List, Any
+from typing import Dict, List, Any, Union
 import json
 
 from ..utils import FloatInt, FractionLike
@@ -178,7 +178,7 @@ def to_unicode(self) -> str:
                 s += "{:d}/{:d}π)".format(phase.numerator,phase.denominator)
         return s
 
-    def to_dict(self) -> dict[str, Any]:
+    def to_dict(self) -> Dict[str, Any]:
         d = {"power2": self.power2, "phase": str(self.phase)}
         if abs(self.floatfactor - 1) > 0.00001:
             d["floatfactor"] =  self.floatfactor
@@ -194,7 +194,7 @@ def to_json(self) -> str:
         return json.dumps(self.to_dict())
 
     @classmethod
-    def from_json(cls, s: str|dict[str,Any]) -> 'Scalar':
+    def from_json(cls, s: Union[str,dict[str,Any]]) -> 'Scalar':
         if isinstance(s, str):
             d = json.loads(s)
         else: