diff --git a/README.md b/README.md
index d0a8815..8dc93e1 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,7 @@
 
 Requirements:
 * python >= 3.10 (written and tested with 3.11)
+* numpy
 
 
 Install with pip:
diff --git a/g85/__init__.py b/g85/__init__.py
index 69c0e4b..8df75f7 100644
--- a/g85/__init__.py
+++ b/g85/__init__.py
@@ -1,9 +1,6 @@
-from .main import (
-    Map as Map,
-    Device as Device,
-    )
-from .read import read as read
-from .write import write as write
+from .main import Map, Device
+from .read import read
+from .write import write
 
 __author__ = 'Jan Petykiewicz'
-__version__ = '0.7'
+__version__ = '0.6'
diff --git a/g85/read.py b/g85/read.py
index 8c4a924..9fd2317 100644
--- a/g85/read.py
+++ b/g85/read.py
@@ -58,24 +58,22 @@ def read_devices(el_map: ElementTree.Element) -> list[Device]:
 
         device = Device(BinType=bin_type, NullBin=null_bin)
 
+        val: Any
         for key, val in el_device.attrib.items():
             if key in ('BinType', 'NullBin'):
                 continue
 
-            parsed_val: Any
             if key in ('WaferSize', 'DeviceSizeX', 'DeviceSizeY', 'Orientation'):
-                parsed_val = float(val)
+                val = float(val)
             elif key in ('OriginLocation',):
-                parsed_val = int(val)
+                val = int(val)
             elif key == 'CreateDate':
-                parsed_val = datetime.datetime.strptime(val + '000', '%Y%m%d%H%M%S%f')
-            else:
-                parsed_val = val
+                val = datetime.datetime.strptime(val + '000', '%Y%m%d%H%M%S%f')
 
             if key in dev_fields and key[0].isupper():
-                setattr(device, key, parsed_val)
+                setattr(device, key, val)
             else:
-                device.misc[key] = parsed_val
+                device.misc[key] = val
 
         for el_entry in el_device:
             tag = _tag(el_entry)
@@ -139,7 +137,7 @@ def read_row(el_row: ElementTree.Element) -> list[str]:
 
 
 def _tag(element: ElementTree.Element) -> str:
-    """
+    '''
     Get the element's tag, excluding any namespaces.
-    """
+    '''
     return element.tag.split('}')[-1]
diff --git a/g85/write.py b/g85/write.py
index e0c0bd3..06d4726 100644
--- a/g85/write.py
+++ b/g85/write.py
@@ -1,5 +1,4 @@
-from typing import TextIO, cast
-from collections.abc import Sequence
+from typing import Sequence, TextIO, cast
 import logging
 import math
 from dataclasses import fields
@@ -11,15 +10,12 @@ from .main import Map, Device
 logger = logging.getLogger(__name__)
 
 
-class G85Error(Exception):
-    pass
-
-
 # Hack to directly pass through <![CDATA[...]]>
-def _escape_cdata(text: str) -> str:
+def _escape_cdata(text):
     if text.startswith('<![CDATA[') and text.endswith(']]>'):
         return text
-    return _original_escape_cdata(text)
+    else:
+        return _original_escape_cdata(text)
 
 
 _original_escape_cdata = ElementTree._escape_cdata      # type: ignore
@@ -68,7 +64,7 @@ def write_devices(devices: Sequence[Device], el_map: ElementTree.Element) -> Non
 
         # Row data prep
         if device.map is None:
-            raise G85Error(f'No _data for device pformat({device})')
+            raise Exception(f'No _data for device pformat({device})')
 
         is_decimal = device.BinType == 'Decimal'
         row_texts, bin_length = prepare_data(device.map, decimal=is_decimal)
@@ -140,7 +136,7 @@ def prepare_data(data: list[list[str]] | list[list[int]], decimal: bool) -> tupl
                 row_text = ' '.join(srow) + ' '
             row_texts.append(row_text)
         return row_texts, char_len
-    else:       # noqa: RET505
+    else:
         data = cast(list[list[int]], data)
         max_value = max(max(rr) for rr in data)
         max_digits = math.ceil(math.log10(max_value))
diff --git a/pyproject.toml b/pyproject.toml
index 3aef2fb..3d9e1e2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -38,41 +38,8 @@ classifiers = [
 requires-python = ">=3.10"
 dynamic = ["version"]
 dependencies = [
+    "numpy~=1.21",
     ]
 
 [tool.hatch.version]
 path = "g85/__init__.py"
-
-
-[tool.ruff]
-exclude = [
-    ".git",
-    "dist",
-    ]
-line-length = 145
-indent-width = 4
-lint.dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"
-lint.select = [
-    "NPY", "E", "F", "W", "B", "ANN", "UP", "SLOT", "SIM", "LOG",
-    "C4", "ISC", "PIE", "PT", "RET", "TCH", "PTH", "INT",
-    "ARG", "PL", "R", "TRY",
-    "G010", "G101", "G201", "G202",
-    "Q002", "Q003", "Q004",
-    ]
-lint.ignore = [
-    #"ANN001",   # No annotation
-    "ANN002",   # *args
-    "ANN003",   # **kwargs
-    "ANN401",   # Any
-    "ANN101",   # self: Self
-    "SIM108",   # single-line if / else assignment
-    "RET504",   # x=y+z; return x
-    "PIE790",   # unnecessary pass
-    "ISC003",   # non-implicit string concatenation
-    "C408",     # dict(x=y) instead of {'x': y}
-    "PLR09",    # Too many xxx
-    "PLR2004",  # magic number
-    "PLC0414",  # import x as x
-    "TRY003",   # Long exception message
-    ]
-